PIC16LF84A-04I/SOVAO [MICROCHIP]

8-BIT, FLASH, 2 MHz, RISC MICROCONTROLLER, PDSO18, 0.300 INCH, LEAD FREE, PLASTIC, SOIC-18;
PIC16LF84A-04I/SOVAO
型号: PIC16LF84A-04I/SOVAO
厂家: MICROCHIP    MICROCHIP
描述:

8-BIT, FLASH, 2 MHz, RISC MICROCONTROLLER, PDSO18, 0.300 INCH, LEAD FREE, PLASTIC, SOIC-18

时钟 光电二极管 外围集成电路
文件: 总90页 (文件大小:1822K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
PIC16F84A  
18-pin Enhanced FLASH/EEPROM 8-Bit Microcontroller  
High Performance RISC CPU Features:  
Pin Diagrams  
PDIP, SOIC  
• Only 35 single word instructions to learn  
• All instructions single-cycle except for program  
branches which are two-cycle  
1  
2
3
4
5
6
7
8
9
RA2  
RA3  
18  
17  
16  
15  
14  
13  
12  
11  
10  
RA1  
RA0  
• Operating speed: DC - 20 MHz clock input  
DC - 200 ns instruction cycle  
RA4/T0CKI  
MCLR  
VSS  
OSC1/CLKIN  
OSC2/CLKOUT  
VDD  
• 1024 words of program memory  
• 68 bytes of Data RAM  
RB0/INT  
RB1  
RB7  
RB6  
• 64 bytes of Data EEPROM  
• 14-bit wide instruction words  
• 8-bit wide data bytes  
RB2  
RB5  
RB3  
RB4  
• 15 Special Function Hardware registers  
• Eight-level deep hardware stack  
• Direct, indirect and relative addressing modes  
• Four interrupt sources:  
SSOP  
- External RB0/INT pin  
RA2  
RA3  
1  
2
3
4
5
6
7
8
9
RA1  
RA0  
20  
19  
18  
17  
16  
15  
14  
13  
12  
11  
- TMR0 timer overflow  
- PORTB<7:4> interrupt-on-change  
- Data EEPROM write complete  
RA4/T0CKI  
MCLR  
OSC1/CLKIN  
OSC2/CLKOUT  
VSS  
VDD  
VDD  
RB7  
RB6  
RB5  
RB4  
Peripheral Features:  
VSS  
RB0/INT  
RB1  
• 13 I/O pins with individual direction control  
• High current sink/source for direct LED drive  
- 25 mA sink max. per pin  
RB2  
10  
RB3  
- 25 mA source max. per pin  
• TMR0: 8-bit timer/counter with 8-bit  
programmable prescaler  
Special Microcontroller Features:  
CMOS Enhanced FLASH/EEPROM  
Technology:  
• 10,000 erase/write cycles Enhanced FLASH  
Program memory typical  
• Low power, high speed technology  
• Fully static design  
• 10,000,000 typical erase/write cycles EEPROM  
Data memory typical  
• Wide operating voltage range:  
- Commercial: 2.0V to 5.5V  
• EEPROM Data Retention > 40 years  
• In-Circuit Serial Programming™ (ICSP™) - via  
two pins  
- Industrial:  
2.0V to 5.5V  
• Low power consumption:  
• Power-on Reset (POR), Power-up Timer (PWRT),  
Oscillator Start-up Timer (OST)  
- < 2 mA typical @ 5V, 4 MHz  
- 15 A typical @ 2V, 32 kHz  
- < 0.5 A typical standby current @ 2V  
• Watchdog Timer (WDT) with its own On-Chip RC  
Oscillator for reliable operation  
• Code protection  
• Power saving SLEEP mode  
• Selectable oscillator options  
2001-2013 Microchip Technology Inc.  
DS35007C-page 1  
PIC16F84A  
Table of Contents  
1.0 Device Overview .......................................................................................................................................................................... 3  
2.0 Memory Organization................................................................................................................................................................... 5  
3.0 Data EEPROM Memory ............................................................................................................................................................. 13  
4.0 I/O Ports ..................................................................................................................................................................................... 15  
5.0 Timer0 Module ........................................................................................................................................................................... 19  
6.0 Special Features of the CPU...................................................................................................................................................... 21  
7.0 Instruction Set Summary............................................................................................................................................................ 35  
8.0 Development Support................................................................................................................................................................. 43  
9.0 Electrical Characteristics ............................................................................................................................................................ 47  
10.0 DC/AC Characteristic Graphs .................................................................................................................................................... 59  
11.0 Packaging Information................................................................................................................................................................ 69  
Appendix A: Revision History .............................................................................................................................................................. 77  
Appendix B: Conversion Considerations.............................................................................................................................................. 78  
Appendix C: Migration from Baseline to  
Mid-range Devices80  
INDEX .................................................................................................................................................................................................. 81  
The Microchip Web Site....................................................................................................................................................................... 85  
Customer Change Notification Service ................................................................................................................................................ 85  
Customer Support................................................................................................................................................................................ 85  
Reader Response ................................................................................................................................................................................ 86  
PIC16F84A Product Identification System........................................................................................................................................... 87  
TO OUR VALUED CUSTOMERS  
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip  
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and  
enhanced as new volumes and updates are introduced.  
If you have any questions or comments regarding this publication, please contact the Marketing Communications Department via  
E-mail at docerrors@microchip.com or fax the Reader Response Form in the back of this data sheet to (480) 792-4150. We  
welcome your feedback.  
Most Current Data Sheet  
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:  
http://www.microchip.com  
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.  
The last character of the literature number is the version number, (e.g., DS30000A is version A of document DS30000).  
Errata  
An errata sheet, describing minor operational differences from the data sheet and recommended workarounds, may exist for current  
devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the revision  
of silicon and revision of document to which it applies.  
To determine if an errata sheet exists for a particular device, please check with one of the following:  
Microchip’s Worldwide Web site; http://www.microchip.com  
Your local Microchip sales office (see last page)  
When contacting a sales office, please specify which device, revision of silicon and data sheet (include literature number) you are  
using.  
Customer Notification System  
Register on our web site at www.microchip.com to receive the most current information on all of our products.  
DS35007C-page 2  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
The program memory contains 1K words, which trans-  
lates to 1024 instructions, since each 14-bit program  
memory word is the same width as each device instruc-  
tion. The data memory (RAM) contains 68 bytes. Data  
EEPROM is 64 bytes.  
1.0  
DEVICE OVERVIEW  
This document contains device specific information for  
the operation of the PIC16F84A device. Additional  
information may be found in the PIC® Mid-Range Ref-  
erence Manual, (DS33023), which may be downloaded  
from the Microchip website. The Reference Manual  
should be considered a complementary document to  
this data sheet, and is highly recommended reading for  
a better understanding of the device architecture and  
operation of the peripheral modules.  
There are also 13 I/O pins that are user-configured on  
a pin-to-pin basis. Some pins are multiplexed with other  
device functions. These functions include:  
• External interrupt  
• Change on PORTB interrupt  
• Timer0 clock input  
The PIC16F84A belongs to the mid-range family of the  
PIC® microcontroller devices. A block diagram of the  
device is shown in Figure 1-1.  
Table 1-1 details the pinout of the device with descrip-  
tions and details for each pin.  
FIGURE 1-1:  
PIC16F84A BLOCK DIAGRAM  
Data Bus  
13  
8
Program Counter  
EEPROM Data Memory  
FLASH  
Program  
Memory  
EEPROM  
Data Memory  
64 x 8  
RAM  
8 Level Stack  
EEDATA  
1K x 14  
File Registers  
(13-bit)  
68 x 8  
Program  
Bus  
14  
7
RAM Addr  
EEADR  
Addr Mux  
Instruction Register  
TMR0  
7
Indirect  
Addr  
Direct Addr  
5
FSR reg  
RA4/T0CKI  
STATUS reg  
MUX  
8
Power-up  
Timer  
I/O Ports  
8
Instruction  
Decode &  
Control  
Oscillator  
Start-up Timer  
ALU  
Power-on  
Reset  
RA3:RA0  
RB7:RB1  
Watchdog  
Timer  
Timing  
Generation  
W reg  
RB0/INT  
MCLR  
OSC2/CLKOUT  
OSC1/CLKIN  
VDD, VSS  
2001-2013 Microchip Technology Inc.  
DS35007C-page 3  
PIC16F84A  
TABLE 1-1:  
PIC16F84A PINOUT DESCRIPTION  
PDIP SOIC SSOP I/O/P  
Buffer  
Type  
Pin Name  
Description  
No.  
No.  
No.  
Type  
OSC1/CLKIN  
16  
16  
15  
18  
19  
I
ST/CMOS(3) Oscillator crystal input/external clock source input.  
OSC2/CLKOUT 15  
O
Oscillator crystal output. Connects to crystal or  
resonator in Crystal Oscillator mode. In RC mode,  
OSC2 pin outputs CLKOUT, which has 1/4 the  
frequency of OSC1 and denotes the instruction  
cycle rate.  
MCLR  
4
4
4
I/P  
ST  
Master Clear (Reset) input/programming voltage  
input. This pin is an active low RESET to the device.  
PORTA is a bi-directional I/O port.  
RA0  
17  
18  
1
17  
18  
1
19  
20  
1
I/O  
I/O  
I/O  
I/O  
I/O  
TTL  
TTL  
TTL  
TTL  
ST  
RA1  
RA2  
RA3  
2
2
2
RA4/T0CKI  
3
3
3
Can also be selected to be the clock input to the  
TMR0 timer/counter. Output is open drain type.  
PORTB is a bi-directional I/O port. PORTB can be  
software programmed for internal weak pull-up on  
all inputs.  
RB0/INT  
6
6
7
I/O  
TTL/ST(1)  
RB0/INT can also be selected as an external  
interrupt pin.  
RB1  
RB2  
RB3  
RB4  
RB5  
RB6  
7
8
7
8
8
I/O  
I/O  
I/O  
I/O  
I/O  
I/O  
TTL  
TTL  
9
9
9
10  
11  
12  
13  
TTL  
10  
11  
12  
10  
11  
12  
TTL  
Interrupt-on-change pin.  
Interrupt-on-change pin.  
TTL  
TTL/ST(2)  
Interrupt-on-change pin.  
Serial programming clock.  
RB7  
13  
13  
14  
I/O  
TTL/ST(2)  
Interrupt-on-change pin.  
Serial programming data.  
VSS  
5
5
5,6  
P
P
Ground reference for logic and I/O pins.  
Positive supply for logic and I/O pins.  
VDD  
14  
14  
15,16  
Legend: I= input  
O = Output  
— = Not used  
I/O = Input/Output  
TTL = TTL input  
P = Power  
ST = Schmitt Trigger input  
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.  
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.  
3: This buffer is a Schmitt Trigger input when configured in RC oscillator mode and a CMOS input otherwise.  
DS35007C-page 4  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 2-1:  
PROGRAM MEMORY MAP  
AND STACK - PIC16F84A  
2.0  
MEMORY ORGANIZATION  
There are two memory blocks in the PIC16F84A.  
These are the program memory and the data memory.  
Each block has its own bus, so that access to each  
block can occur during the same oscillator cycle.  
PC<12:0>  
13  
CALL, RETURN  
RETFIE, RETLW  
Stack Level 1  
The data memory can further be broken down into the  
general purpose RAM and the Special Function  
Registers (SFRs). The operation of the SFRs that  
control the “core” are described here. The SFRs used  
to control the peripheral modules are described in the  
section discussing each individual peripheral module.  
Stack Level 8  
0000h  
0004h  
RESET Vector  
Peripheral Interrupt Vector  
The data memory area also contains the data  
EEPROM memory. This memory is not directly mapped  
into the data memory, but is indirectly mapped. That is,  
an indirect address pointer specifies the address of the  
data EEPROM memory to read/write. The 64 bytes of  
data EEPROM memory have the address range  
0h-3Fh. More details on the EEPROM memory can be  
found in Section 3.0.  
Additional information on device memory may be found  
in the PIC® Mid-Range Reference Manual, (DS33023).  
3FFh  
2.1  
Program Memory Organization  
The PIC16FXX has a 13-bit program counter capable  
of addressing an 8K x 14 program memory space. For  
the PIC16F84A, the first 1K x 14 (0000h-03FFh) are  
physically implemented (Figure 2-1). Accessing a loca-  
tion above the physically implemented address will  
cause a wraparound. For example, for locations 20h,  
420h, 820h, C20h, 1020h, 1420h, 1820h, and 1C20h,  
the instruction will be the same.  
1FFFh  
The RESET vector is at 0000h and the interrupt vector  
is at 0004h.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 5  
PIC16F84A  
FIGURE 2-2:  
REGISTER FILE MAP -  
PIC16F84A  
2.2  
Data Memory Organization  
The data memory is partitioned into two areas. The first  
is the Special Function Registers (SFR) area, while the  
second is the General Purpose Registers (GPR) area.  
The SFRs control the operation of the device.  
File Address  
File Address  
80h  
(1)  
(1)  
00h  
Indirect addr.  
Indirect addr.  
01h  
02h  
TMR0  
PCL  
OPTION_REG  
PCL  
81h  
82h  
Portions of data memory are banked. This is for both  
the SFR area and the GPR area. The GPR area is  
banked to allow greater than 116 bytes of general  
purpose RAM. The banked areas of the SFR are for the  
registers that control the peripheral functions. Banking  
requires the use of control bits for bank selection.  
These control bits are located in the STATUS Register.  
Figure 2-2 shows the data memory map organization.  
03h  
04h  
05h  
06h  
STATUS  
FSR  
STATUS  
FSR  
83h  
84h  
85h  
86h  
PORTA  
TRISA  
PORTB  
TRISB  
07h  
08h  
09h  
87h  
88h  
89h  
Instructions MOVWF and MOVF can move values from  
the W register to any location in the register file (“F”),  
and vice-versa.  
EEDATA  
EEADR  
EECON1  
(1)  
EECON2  
0Ah  
PCLATH  
INTCON  
PCLATH  
INTCON  
8Ah  
The entire data memory can be accessed either  
directly using the absolute address of each register file  
or indirectly through the File Select Register (FSR)  
(Section 2.5). Indirect addressing uses the present  
value of the RP0 bit for access into the banked areas of  
data memory.  
0Bh  
0Ch  
8Bh  
8Ch  
68  
General  
Purpose  
Registers  
(SRAM)  
Mapped  
(accesses)  
in Bank 0  
Data memory is partitioned into two banks which  
contain the general purpose registers and the special  
function registers. Bank 0 is selected by clearing the  
RP0 bit (STATUS<5>). Setting the RP0 bit selects Bank  
1. Each Bank extends up to 7Fh (128 bytes). The first  
twelve locations of each Bank are reserved for the  
Special Function Registers. The remainder are Gen-  
eral Purpose Registers, implemented as static RAM.  
4Fh  
50h  
CFh  
D0h  
2.2.1  
GENERAL PURPOSE REGISTER  
FILE  
Each General Purpose Register (GPR) is 8-bits wide  
and is accessed either directly or indirectly through the  
FSR (Section 2.5).  
7Fh  
FFh  
The GPR addresses in Bank 1 are mapped to  
addresses in Bank 0. As an example, addressing loca-  
tion 0Ch or 8Ch will access the same GPR.  
Bank 0  
Bank 1  
Unimplemented data memory location, read as '0'.  
Note 1: Not a physical register.  
DS35007C-page 6  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
The special function registers can be classified into two  
sets, core and peripheral. Those associated with the  
core functions are described in this section. Those  
related to the operation of the peripheral features are  
described in the section for that specific feature.  
2.3  
Special Function Registers  
The Special Function Registers (Figure 2-2 and  
Table 2-1) are used by the CPU and Peripheral  
functions to control the device operation. These  
registers are static RAM.  
TABLE 2-1:  
SPECIAL FUNCTION REGISTER FILE SUMMARY  
Value on  
Details  
Addr  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
Power-on  
RESET  
on page  
Bank 0  
00h INDF  
01h TMR0  
02h PCL  
Uses contents of FSR to address Data Memory (not a physical register)  
8-bit Real-Time Clock/Counter  
---- ----  
xxxx xxxx  
0000 0000  
11  
20  
11  
8
Low Order 8 bits of the Program Counter (PC)  
(2)  
03h  
STATUS  
IRP  
RP1  
RP0  
TO  
PD  
Z
DC  
C
0001 1xxx  
xxxx xxxx  
---x xxxx  
04h FSR  
Indirect Data Memory Address Pointer 0  
11  
16  
18  
(4)  
05h PORTA  
06h PORTB  
RA4/T0CKI  
RB4  
RA3  
RB3  
RA2  
RB2  
RA1  
RA0  
(5)  
RB7  
RB6  
RB5  
RB1 RB0/INT xxxx xxxx  
07h  
Unimplemented location, read as '0'  
EEPROM Data Register  
08h EEDATA  
09h EEADR  
xxxx xxxx 13,14  
xxxx xxxx 13,14  
EEPROM Address Register  
(1)  
0Ah  
11  
PCLATH  
Write Buffer for upper 5 bits of the PC  
INTE RBIE T0IF INTF  
---0 0000  
0Bh INTCON  
Bank 1  
GIE  
EEIE  
T0IE  
RBIF  
0000 000x  
10  
80h INDF  
Uses Contents of FSR to address Data Memory (not a physical register)  
---- ----  
11  
9
81h  
82h PCL  
83h  
OPTION_REG RBPU INTEDG  
Low order 8 bits of Program Counter (PC)  
IRP RP1 RP0 TO  
Indirect data memory address pointer 0  
PORTA Data Direction Register  
PORTB Data Direction Register  
Unimplemented location, read as '0'  
EEIF  
EEPROM Control Register 2 (not a physical register)  
T0CS  
T0SE  
PSA  
PS2  
PS1  
PS0  
C
1111 1111  
0000 0000  
11  
8
(2)  
STATUS  
PD  
Z
DC  
0001 1xxx  
xxxx xxxx  
---1 1111  
1111 1111  
84h FSR  
85h TRISA  
86h TRISB  
87h  
11  
16  
18  
13  
14  
88h EECON1  
WRERR WREN  
WR  
RD  
---0 x000  
89h  
0Ah  
EECON2  
PCLATH  
---- ----  
(1)  
11  
10  
Write buffer for upper 5 bits of the PC  
INTE RBIE T0IF  
---0 0000  
0000 000x  
0Bh INTCON  
GIE  
EEIE  
T0IE  
INTF  
RBIF  
Legend: x= unknown, u= unchanged. -= unimplemented, read as '0', q= value depends on condition  
Note 1: The upper byte of the program counter is not directly accessible. PCLATH is a slave register for PC<12:8>. The contents  
of PCLATH can be transferred to the upper byte of the program counter, but the contents of PC<12:8> are never trans-  
ferred to PCLATH.  
2: The TO and PD status bits in the STATUS register are not affected by a MCLR Reset.  
3: Other (non power-up) RESETS include: external RESET through MCLR and the Watchdog Timer Reset.  
4: On any device RESET, these pins are configured as inputs.  
5: This is the value that will be in the port output latch.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 7  
PIC16F84A  
2.3.1  
STATUS REGISTER  
Note 1: The IRP and RP1 bits (STATUS<7:6>)  
are not used by the PIC16F84A and  
should be programmed as cleared. Use of  
these bits as general purpose R/W bits is  
NOT recommended, since this may affect  
upward compatibility with future products.  
The STATUS register contains the arithmetic status of  
the ALU, the RESET status and the bank select bit for  
data memory.  
As with any register, the STATUS register can be the  
destination for any instruction. If the STATUS register is  
the destination for an instruction that affects the Z, DC  
or C bits, then the write to these three bits is disabled.  
These bits are set or cleared according to device logic.  
Furthermore, the TO and PD bits are not writable.  
Therefore, the result of an instruction with the STATUS  
register as destination may be different than intended.  
2: The C and DC bits operate as a borrow  
and digit borrow out bit, respectively, in  
subtraction. See the SUBLW and SUBWF  
instructions for examples.  
3: When the STATUS register is the  
destination for an instruction that affects  
the Z, DC or C bits, then the write to these  
three bits is disabled. The specified bit(s)  
will be updated according to device logic  
For example, CLRF STATUSwill clear the upper three  
bits and set the Z bit. This leaves the STATUS register  
as 000u u1uu(where u= unchanged).  
Only the BCF, BSF, SWAPF and MOVWF instructions  
should be used to alter the STATUS register (Table 7-2),  
because these instructions do not affect any status bit.  
REGISTER 2-1:  
STATUS REGISTER (ADDRESS 03h, 83h)  
R/W-0  
IRP  
R/W-0  
RP1  
R/W-0  
RP0  
R-1  
TO  
R-1  
PD  
R/W-x  
Z
R/W-x  
DC  
R/W-x  
C
bit 7  
bit 0  
bit 7-6  
bit 5  
Unimplemented: Maintain as ‘0’  
RP0: Register Bank Select bits (used for direct addressing)  
01= Bank 1 (80h - FFh)  
00= Bank 0 (00h - 7Fh)  
bit 4  
bit 3  
bit 2  
bit 1  
TO: Time-out bit  
1= After power-up, CLRWDTinstruction, or SLEEPinstruction  
0= A WDT time-out occurred  
PD: Power-down bit  
1= After power-up or by the CLRWDTinstruction  
0= By execution of the SLEEPinstruction  
Z: Zero bit  
1= The result of an arithmetic or logic operation is zero  
0= The result of an arithmetic or logic operation is not zero  
DC: Digit carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWFinstructions) (for borrow, the polarity  
is reversed)  
1= A carry-out from the 4th low order bit of the result occurred  
0= No carry-out from the 4th low order bit of the result  
bit 0  
C: Carry/borrow bit (ADDWF, ADDLW,SUBLW,SUBWF instructions) (for borrow, the polarity is  
reversed)  
1= A carry-out from the Most Significant bit of the result occurred  
0= No carry-out from the Most Significant bit of the result occurred  
Note: A subtraction is executed by adding the two’s complement of the second operand.  
For rotate (RRF, RLF) instructions, this bit is loaded with either the high or low order  
bit of the source register.  
Legend:  
R = Readable bit  
- n = Value at POR  
W = Writable bit  
’1’ = Bit is set  
U = Unimplemented bit, read as ‘0’  
’0’ = Bit is cleared  
x = Bit is unknown  
DS35007C-page 8  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
2.3.2  
OPTION REGISTER  
Note: When the prescaler is assigned to  
the WDT (PSA = '1'), TMR0 has a 1:1  
prescaler assignment.  
The OPTION register is a readable and writable  
register which contains various control bits to configure  
the TMR0/WDT prescaler, the external INT interrupt,  
TMR0, and the weak pull-ups on PORTB.  
REGISTER 2-2:  
OPTION REGISTER (ADDRESS 81h)  
R/W-1  
RBPU  
R/W-1  
R/W-1  
T0CS  
R/W-1  
T0SE  
R/W-1  
PSA  
R/W-1  
PS2  
R/W-1  
PS1  
R/W-1  
PS0  
INTEDG  
bit 7  
bit 0  
bit 7  
bit 6  
bit 5  
bit 4  
bit 3  
bit 2-0  
RBPU: PORTB Pull-up Enable bit  
1= PORTB pull-ups are disabled  
0= PORTB pull-ups are enabled by individual port latch values  
INTEDG: Interrupt Edge Select bit  
1= Interrupt on rising edge of RB0/INT pin  
0= Interrupt on falling edge of RB0/INT pin  
T0CS: TMR0 Clock Source Select bit  
1= Transition on RA4/T0CKI pin  
0= Internal instruction cycle clock (CLKOUT)  
T0SE: TMR0 Source Edge Select bit  
1= Increment on high-to-low transition on RA4/T0CKI pin  
0= Increment on low-to-high transition on RA4/T0CKI pin  
PSA: Prescaler Assignment bit  
1= Prescaler is assigned to the WDT  
0= Prescaler is assigned to the Timer0 module  
PS2:PS0: Prescaler Rate Select bits  
Bit Value TMR0 Rate WDT Rate  
000  
001  
010  
011  
100  
101  
110  
111  
1 : 1  
1 : 2  
1 : 4  
1 : 8  
1 : 16  
1 : 32  
1 : 64  
1 : 128  
1 : 2  
1 : 4  
1 : 8  
1 : 16  
1 : 32  
1 : 64  
1 : 128  
1 : 256  
Legend:  
R = Readable bit  
W = Writable bit  
’1’ = Bit is set  
U = Unimplemented bit, read as ‘0’  
- n = Value at POR  
’0’ = Bit is cleared  
x = Bit is unknown  
2001-2013 Microchip Technology Inc.  
DS35007C-page 9  
PIC16F84A  
2.3.3  
INTCON REGISTER  
Note: Interrupt flag bits are set when an interrupt  
condition occurs, regardless of the state of  
its corresponding enable bit or the global  
enable bit, GIE (INTCON<7>).  
The INTCON register is a readable and writable  
register that contains the various enable bits for all  
interrupt sources.  
REGISTER 2-3:  
INTCON REGISTER (ADDRESS 0Bh, 8Bh)  
R/W-0  
GIE  
R/W-0  
EEIE  
R/W-0  
T0IE  
R/W-0  
INTE  
R/W-0  
RBIE  
R/W-0  
T0IF  
R/W-0  
INTF  
R/W-x  
RBIF  
bit 7  
bit 0  
bit 7  
bit 6  
bit 5  
bit 4  
bit 3  
bit 2  
bit 1  
bit 0  
GIE: Global Interrupt Enable bit  
1= Enables all unmasked interrupts  
0= Disables all interrupts  
EEIE: EE Write Complete Interrupt Enable bit  
1= Enables the EE Write Complete interrupts  
0= Disables the EE Write Complete interrupt  
T0IE: TMR0 Overflow Interrupt Enable bit  
1= Enables the TMR0 interrupt  
0= Disables the TMR0 interrupt  
INTE: RB0/INT External Interrupt Enable bit  
1= Enables the RB0/INT external interrupt  
0= Disables the RB0/INT external interrupt  
RBIE: RB Port Change Interrupt Enable bit  
1= Enables the RB port change interrupt  
0= Disables the RB port change interrupt  
T0IF: TMR0 Overflow Interrupt Flag bit  
1= TMR0 register has overflowed (must be cleared in software)  
0= TMR0 register did not overflow  
INTF: RB0/INT External Interrupt Flag bit  
1= The RB0/INT external interrupt occurred (must be cleared in software)  
0= The RB0/INT external interrupt did not occur  
RBIF: RB Port Change Interrupt Flag bit  
1= At least one of the RB7:RB4 pins changed state (must be cleared in software)  
0= None of the RB7:RB4 pins have changed state  
Legend:  
R = Readable bit  
W = Writable bit  
’1’ = Bit is set  
U = Unimplemented bit, read as ‘0’  
’0’ = Bit is cleared x = Bit is unknown  
- n = Value at POR  
DS35007C-page 10  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
2.4  
PCL and PCLATH  
2.5  
Indirect Addressing; INDF and  
FSR Registers  
The program counter (PC) specifies the address of the  
instruction to fetch for execution. The PC is 13 bits  
wide. The low byte is called the PCL register. This reg-  
ister is readable and writable. The high byte is called  
the PCH register. This register contains the PC<12:8>  
bits and is not directly readable or writable. If the pro-  
gram counter (PC) is modified or a conditional test is  
true, the instruction requires two cycles. The second  
cycle is executed as a NOP. All updates to the PCH reg-  
ister go through the PCLATH register.  
The INDF register is not a physical register. Addressing  
INDF actually addresses the register whose address is  
contained in the FSR register (FSR is a pointer). This is  
indirect addressing.  
EXAMPLE 2-1:  
INDIRECT ADDRESSING  
• Register file 05 contains the value 10h  
• Register file 06 contains the value 0Ah  
• Load the value 05 into the FSR register  
2.4.1  
STACK  
• A read of the INDF register will return the value  
of 10h  
The stack allows a combination of up to 8 program calls  
and interrupts to occur. The stack contains the return  
address from this branch in program execution.  
• Increment the value of the FSR register by one  
(FSR = 06)  
• A read of the INDF register now will return the  
value of 0Ah.  
Mid-range devices have an 8 level deep x 13-bit wide  
hardware stack. The stack space is not part of either  
program or data space and the stack pointer is not  
readable or writable. The PC is PUSHed onto the stack  
when a CALL instruction is executed or an interrupt  
causes a branch. The stack is POPed in the event of a  
RETURN, RETLW or a RETFIE instruction execution.  
PCLATH is not modified when the stack is PUSHed or  
POPed.  
Reading INDF itself indirectly (FSR = 0) will produce  
00h. Writing to the INDF register indirectly results in a  
no-operation (although STATUS bits may be affected).  
A simple program to clear RAM locations 20h-2Fh  
using indirect addressing is shown in Example 2-2.  
After the stack has been PUSHed eight times, the ninth  
push overwrites the value that was stored from the first  
push. The tenth push overwrites the second push (and  
so on).  
EXAMPLE 2-2:  
HOW TO CLEAR RAM  
USING INDIRECT  
ADDRESSING  
movlw  
movwf  
0x20  
;initialize pointer  
;to RAM  
FSR  
NEXT  
clrf  
incf  
btfss  
goto  
INDF  
FSR  
FSR,4  
NEXT  
;clear INDF register  
;inc pointer  
;all done?  
;NO, clear next  
CONTINUE  
:
;YES, continue  
An effective 9-bit address is obtained by concatenating  
the 8-bit FSR register and the IRP bit (STATUS<7>), as  
shown in Figure 2-3. However, IRP is not used in the  
PIC16F84A.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 11  
PIC16F84A  
FIGURE 2-3:  
DIRECT/INDIRECT ADDRESSING  
Indirect Addressing  
Direct Addressing  
From Opcode  
(FSR)  
RP1 RP0  
6
0
IRP  
7
0
(2)  
(2)  
Bank Select  
Location Select  
Location Select  
Bank Select  
00  
01  
00h  
80h  
0Bh  
0Ch  
Addresses  
map back to  
Bank 0  
Data  
(1)  
Memory  
4Fh  
50h  
(3)  
(3)  
7Fh  
FFh  
Bank 0  
Note 1: For memory map detail, see Figure 2-2.  
Bank 1  
2: Maintain as clear for upward compatibility with future products.  
3: Not implemented.  
DS35007C-page 12  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
The EEPROM data memory allows byte read and write.  
A byte write automatically erases the location and  
writes the new data (erase before write). The EEPROM  
data memory is rated for high erase/write cycles. The  
write time is controlled by an on-chip timer. The write-  
time will vary with voltage and temperature as well as  
from chip to chip. Please refer to AC specifications for  
exact limits.  
3.0  
DATA EEPROM MEMORY  
The EEPROM data memory is readable and writable  
during normal operation (full VDD range). This memory  
is not directly mapped in the register file space. Instead  
it is indirectly addressed through the Special Function  
Registers. There are four SFRs used to read and write  
this memory. These registers are:  
• EECON1  
When the device is code protected, the CPU may  
continue to read and write the data EEPROM memory.  
The device programmer can no longer access  
this memory.  
• EECON2 (not a physically implemented register)  
• EEDATA  
• EEADR  
Additional information on the Data EEPROM is avail-  
able in the PIC® Mid-Range Reference Manual  
(DS33023).  
EEDATA holds the 8-bit data for read/write, and  
EEADR holds the address of the EEPROM location  
being accessed. PIC16F84A devices have 64 bytes of  
data EEPROM with an address range from 0h to 3Fh.  
REGISTER 3-1:  
EECON1 REGISTER (ADDRESS 88h)  
U-0  
U-0  
U-0  
R/W-0  
EEIF  
R/W-x  
R/W-0  
WREN  
R/S-0  
WR  
R/S-0  
RD  
WRERR  
bit 7  
bit 0  
bit 7-5  
bit 4  
Unimplemented: Read as '0'  
EEIF: EEPROM Write Operation Interrupt Flag bit  
1= The write operation completed (must be cleared in software)  
0= The write operation is not complete or has not been started  
bit 3  
WRERR: EEPROM Error Flag bit  
1= A write operation is prematurely terminated  
(any MCLR Reset or any WDT Reset during normal operation)  
0= The write operation completed  
bit 2  
bit 1  
WREN: EEPROM Write Enable bit  
1= Allows write cycles  
0= Inhibits write to the EEPROM  
WR: Write Control bit  
1= Initiates a write cycle. The bit is cleared by hardware once write is complete. The WR bit  
can only be set (not cleared) in software.  
0= Write cycle to the EEPROM is complete  
bit 0  
RD: Read Control bit  
1= Initiates an EEPROM read RD is cleared in hardware. The RD bit can only be set (not  
cleared) in software.  
0= Does not initiate an EEPROM read  
Legend:  
R = Readable bit  
W = Writable bit  
’1’ = Bit is set  
U = Unimplemented bit, read as ‘0’  
’0’ = Bit is cleared x = Bit is unknown  
- n = Value at POR  
2001-2013 Microchip Technology Inc.  
DS35007C-page 13  
PIC16F84A  
Additionally, the WREN bit in EECON1 must be set to  
enable write. This mechanism prevents accidental writes  
to data EEPROM due to errant (unexpected) code exe-  
cution (i.e., lost programs). The user should keep the  
WREN bit clear at all times, except when updating  
EEPROM. The WREN bit is not cleared by hardware.  
3.1  
Reading the EEPROM Data  
Memory  
To read a data memory location, the user must write the  
address to the EEADR register and then set control bit  
RD (EECON1<0>). The data is available, in the very  
next cycle, in the EEDATA register; therefore, it can be  
read in the next instruction. EEDATA will hold this value  
until another read or until it is written to by the user  
(during a write operation).  
After a write sequence has been initiated, clearing the  
WREN bit will not affect this write cycle. The WR bit will  
be inhibited from being set unless the WREN bit is set.  
At the completion of the write cycle, the WR bit is  
cleared in hardware and the EE Write Complete  
Interrupt Flag bit (EEIF) is set. The user can either  
enable this interrupt or poll this bit. EEIF must be  
cleared by software.  
EXAMPLE 3-1:  
DATA EEPROM READ  
BCF  
STATUS, RP0 ; Bank 0  
MOVLW  
MOVWF  
BSF  
BSF  
BCF  
CONFIG_ADDR  
EEADR  
STATUS, RP0 ; Bank 1  
EECON1, RD ; EE Read  
STATUS, RP0 ; Bank 0  
;
; Address to read  
3.3  
Write Verify  
Depending on the application, good programming  
practice may dictate that the value written to the Data  
EEPROM should be verified (Example 3-3) to the  
desired value to be written. This should be used in  
applications where an EEPROM bit will be stressed  
near the specification limit.  
MOVF  
EEDATA, W  
; W = EEDATA  
3.2  
Writing to the EEPROM Data  
Memory  
To write an EEPROM data location, the user must first  
write the address to the EEADR register and the data  
to the EEDATA register. Then the user must follow a  
specific sequence to initiate the write for each byte.  
Generally, the EEPROM write failure will be a bit which  
was written as a '0', but reads back as a '1' (due to  
leakage off the bit).  
EXAMPLE 3-3:  
WRITE VERIFY  
EXAMPLE 3-2:  
DATA EEPROM WRITE  
BCF STATUS,RP0 ; Bank 0  
:
:
MOVF EEDATA,W  
BSF STATUS,RP0 ; Bank 1  
BSF  
BCF  
BSF  
STATUS, RP0 ; Bank 1  
INTCON, GIE ; Disable INTs.  
EECON1, WREN ; Enable Write  
; Any code  
; can go here  
; Must be in Bank 0  
MOVLW  
55h  
;
MOVWF  
MOVLW  
MOVWF  
BSF  
EECON2  
AAh  
EECON2  
EECON1,WR  
; Write 55h  
;
; Write AAh  
; Set WR bit  
READ  
BSF EECON1,RD ; YES, Read the  
; value written  
BCF STATUS,RP0 ; Bank 0  
;
;
begin write  
BSF  
INTCON, GIE ; Enable INTs.  
; Is the value written  
; (in W reg) and  
; read (in EEDATA)  
; the same?  
;
;
The write will not initiate if the above sequence is not  
exactly followed (write 55h to EECON2, write AAh to  
EECON2, then set WR bit) for each byte. We strongly  
recommend that interrupts be disabled during this  
code segment.  
SUBWFEEDATA,W  
BTFSSSTATUS,Z  
; Is difference 0?  
GOTO WRITE_ERR ; NO, Write error  
TABLE 3-1:  
REGISTERS/BITS ASSOCIATED WITH DATA EEPROM  
Value on  
Power-on  
Reset  
Value on  
all other  
RESETS  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
08h  
09h  
88h  
89h  
EEDATA EEPROM Data Register  
xxxx xxxx uuuu uuuu  
xxxx xxxx uuuu uuuu  
---0 x000 ---0 q000  
---- ---- ---- ----  
EEADR  
EEPROM Address Register  
EECON1  
EEIF WRERR WREN  
WR  
RD  
EECON2 EEPROM Control Register 2  
Legend: x= unknown, u= unchanged, -= unimplemented, read as '0', q= value depends upon condition.  
Shaded cells are not used by data EEPROM.  
DS35007C-page 14  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 4-1:  
BLOCK DIAGRAM OF  
PINS RA3:RA0  
4.0  
I/O PORTS  
Some pins for these I/O ports are multiplexed with an  
alternate function for the peripheral features on the  
device. In general, when a peripheral is enabled, that  
pin may not be used as a general purpose I/O pin.  
Data  
Bus  
D
Q
VDD  
P
WR  
Additional information on I/O ports may be found in the  
PIC® Mid-Range Reference Manual (DS33023).  
Port  
Q
CK  
Data Latch  
4.1  
PORTA and TRISA Registers  
I/O pin  
N
PORTA is a 5-bit wide, bi-directional port. The corre-  
sponding data direction register is TRISA. Setting a  
TRISA bit (= 1) will make the corresponding PORTA pin  
an input (i.e., put the corresponding output driver in a  
Hi-Impedance mode). Clearing a TRISA bit (= 0) will  
make the corresponding PORTA pin an output (i.e., put  
the contents of the output latch on the selected pin).  
D
Q
WR  
TRIS  
VSS  
Q
CK  
TRIS Latch  
TTL  
Input  
Buffer  
Note: On a Power-on Reset, these pins are con-  
figured as inputs and read as '0'.  
RD TRIS  
Q
Reading the PORTA register reads the status of the  
pins, whereas writing to it will write to the port latch. All  
write operations are read-modify-write operations.  
Therefore, a write to a port implies that the port pins are  
read. This value is modified and then written to the port  
data latch.  
D
EN  
RD Port  
Pin RA4 is multiplexed with the Timer0 module clock  
input to become the RA4/T0CKI pin. The RA4/T0CKI  
pin is a Schmitt Trigger input and an open drain output.  
All other RA port pins have TTL input levels and full  
CMOS output drivers.  
Note: I/O pins have protection diodes to VDD and VSS.  
FIGURE 4-2:  
BLOCK DIAGRAM OF PIN  
RA4  
EXAMPLE 4-1:  
INITIALIZING PORTA  
Data  
Bus  
BCF  
CLRF  
STATUS,RP0 ;  
PORTA  
D
Q
; Initialize PORTA by  
; clearing output  
; data latches  
WR  
Port  
Q
CK  
RA4 pin  
N
BSF  
STATUS,RP0 ; Select Bank 1  
Data Latch  
MOVLW  
0x0F  
; Value used to  
; initialize data  
; direction  
; Set RA<3:0> as inputs  
; RA4 as output  
VSS  
D
Q
Q
WR  
TRIS  
MOVWF  
TRISA  
CK  
; TRISA<7:5> are always  
; read as '0'.  
TRIS Latch  
Schmitt  
Trigger  
Input  
Buffer  
RD TRIS  
Q
D
EN  
RD Port  
TMR0 Clock Input  
Note: I/O pins have protection diodes to VDD and VSS.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 15  
PIC16F84A  
TABLE 4-1:  
PORTA FUNCTIONS  
Name  
Bit0  
Buffer Type  
Function  
RA0  
bit0  
bit1  
bit2  
bit3  
bit4  
TTL  
TTL  
TTL  
TTL  
ST  
Input/output  
Input/output  
Input/output  
Input/output  
RA1  
RA2  
RA3  
RA4/T0CKI  
Input/output or external clock input for TMR0.  
Output is open drain type.  
Legend: TTL = TTL input, ST = Schmitt Trigger input  
TABLE 4-2:  
SUMMARY OF REGISTERS ASSOCIATED WITH PORTA  
Value on  
Power-on  
Reset  
Value on all  
other  
RESETS  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
05h  
85h  
PORTA  
TRISA  
RA4/T0CKI  
TRISA4  
RA3  
RA2  
RA1  
RA0  
---x xxxx ---u uuuu  
TRISA3 TRISA2 TRISA1 TRISA0 ---1 1111 ---1 1111  
Legend: x= unknown, u= unchanged, -= unimplemented, read as '0'. Shaded cells are unimplemented, read as '0'.  
DS35007C-page 16  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 4-3:  
BLOCK DIAGRAM OF  
PINS RB7:RB4  
4.2  
PORTB and TRISB Registers  
PORTB is an 8-bit wide, bi-directional port. The corre-  
sponding data direction register is TRISB. Setting a  
TRISB bit (= 1) will make the corresponding PORTB pin  
an input (i.e., put the corresponding output driver in a  
Hi-Impedance mode). Clearing a TRISB bit (= 0) will  
make the corresponding PORTB pin an output (i.e., put  
the contents of the output latch on the selected pin).  
VDD  
RBPU(1)  
Weak  
P
Pull-up  
Data Latch  
Data Bus  
WR Port  
D
Q
I/O pin(2)  
CK  
TRIS Latch  
EXAMPLE 4-2:  
BCF  
INITIALIZING PORTB  
D
Q
STATUS,RP0 ;  
PORTB  
CLRF  
; Initialize PORTB by  
; clearing output  
; data latches  
WR TRIS  
TTL  
Input  
Buffer  
CK  
BSF  
STATUS,RP0 ; Select Bank 1  
MOVLW  
0xCF  
; Value used to  
; initialize data  
; direction  
; Set RB<3:0> as inputs  
; RB<5:4> as outputs  
; RB<7:6> as inputs  
RD TRIS  
RD Port  
Latch  
Q
D
MOVWF  
TRISB  
EN  
Set RBIF  
Q
D
Each of the PORTB pins has a weak internal pull-up. A  
single control bit can turn on all the pull-ups. This is per-  
formed by clearing bit RBPU (OPTION<7>). The weak  
pull-up is automatically turned off when the port pin is  
configured as an output. The pull-ups are disabled on a  
Power-on Reset.  
From other  
RB7:RB4 pins  
EN  
RD Port  
Note 1: TRISB = '1' enables weak pull-up  
(if RBPU = '0' in the OPTION_REG register).  
Four of PORTB’s pins, RB7:RB4, have an interrupt-on-  
change feature. Only pins configured as inputs can  
cause this interrupt to occur (i.e., any RB7:RB4 pin  
configured as an output is excluded from the interrupt-  
on-change comparison). The input pins (of RB7:RB4)  
are compared with the old value latched on the last  
read of PORTB. The “mismatch” outputs of RB7:RB4  
are OR’ed together to generate the RB Port Change  
Interrupt with flag bit RBIF (INTCON<0>).  
2: I/O pins have diode protection to VDD and VSS.  
FIGURE 4-4:  
BLOCK DIAGRAM OF  
PINS RB3:RB0  
VDD  
RBPU(1)  
Weak  
P
Pull-up  
Data Latch  
Data Bus  
WR Port  
D
Q
This interrupt can wake the device from SLEEP. The  
user, in the Interrupt Service Routine, can clear the  
interrupt in the following manner:  
I/O pin(2)  
CK  
TRIS Latch  
a) Any read or write of PORTB. This will end the  
mismatch condition.  
D
Q
TTL  
Input  
Buffer  
WR TRIS  
CK  
b) Clear flag bit RBIF.  
A mismatch condition will continue to set flag bit RBIF.  
Reading PORTB will end the mismatch condition and  
allow flag bit RBIF to be cleared.  
RD TRIS  
RD Port  
D
Q
The interrupt-on-change feature is recommended for  
wake-up on key depression operation and operations  
where PORTB is only used for the interrupt-on-change  
feature. Polling of PORTB is not recommended while  
using the interrupt-on-change feature.  
EN  
RB0/INT  
Schmitt Trigger  
Buffer  
RD Port  
Note 1: TRISB = '1' enables weak pull-up  
(if RBPU = '0' in the OPTION_REG register).  
2: I/O pins have diode protection to VDD and VSS.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 17  
PIC16F84A  
TABLE 4-3:  
PORTB FUNCTIONS  
Name  
Bit  
Buffer Type  
I/O Consistency Function  
Input/output pin or external interrupt input.  
RB0/INT  
bit0  
TTL/ST(1)  
Internal software programmable weak pull-up.  
RB1  
RB2  
RB3  
RB4  
bit1  
bit2  
bit3  
bit4  
TTL  
TTL  
TTL  
TTL  
Input/output pin. Internal software programmable weak pull-up.  
Input/output pin. Internal software programmable weak pull-up.  
Input/output pin. Internal software programmable weak pull-up.  
Input/output pin (with interrupt-on-change).  
Internal software programmable weak pull-up.  
RB5  
RB6  
RB7  
bit5  
bit6  
bit7  
TTL  
Input/output pin (with interrupt-on-change).  
Internal software programmable weak pull-up.  
TTL/ST(2)  
TTL/ST(2)  
Input/output pin (with interrupt-on-change).  
Internal software programmable weak pull-up. Serial programming clock.  
Input/output pin (with interrupt-on-change).  
Internal software programmable weak pull-up. Serial programming data.  
Legend: TTL = TTL input, ST = Schmitt Trigger.  
Note 1: This buffer is a Schmitt Trigger input when configured as the external interrupt.  
2: This buffer is a Schmitt Trigger input when used in Serial Programming mode.  
TABLE 4-4:  
SUMMARY OF REGISTERS ASSOCIATED WITH PORTB  
Value on  
Power-on  
Reset  
Value on  
all other  
RESETS  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
06h  
86h  
81h  
PORTB  
TRISB  
OPTION_REG RBPU INTEDG T0CS  
GIE EEIE T0IE  
RB7  
RB6  
RB5  
RB4  
RB3  
RB2  
RB1  
RB0/INT xxxx xxxx uuuu uuuu  
TRISB7 TRISB6 TRISB5 TRISB4 TRISB3 TRISB2 TRISB1 TRISB0 1111 1111 1111 1111  
T0SE  
INTE  
PSA  
PS2  
T0IF  
PS1  
PS0  
1111 1111 1111 1111  
0000 000x 0000 000u  
0Bh,8Bh INTCON  
RBIE  
INTF  
RBIF  
Legend: x= unknown, u= unchanged. Shaded cells are not used by PORTB.  
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PIC16F84A  
Additional information on external clock requirements  
is available in the PIC® Mid-Range Reference Manual,  
(DS33023).  
5.0  
TIMER0 MODULE  
The Timer0 module timer/counter has the following  
features:  
5.2  
Prescaler  
• 8-bit timer/counter  
• Readable and writable  
An 8-bit counter is available as a prescaler for the Timer0  
module, or as a postscaler for the Watchdog Timer,  
respectively (Figure 5-2). For simplicity, this counter is  
being referred to as “prescaler” throughout this data  
sheet. Note that there is only one prescaler available  
which is mutually exclusively shared between the Timer0  
module and the Watchdog Timer. Thus, a prescaler  
assignment for the Timer0 module means that there is no  
prescaler for the Watchdog Timer, and vice-versa.  
• Internal or external clock select  
• Edge select for external clock  
• 8-bit software programmable prescaler  
• Interrupt-on-overflow from FFh to 00h  
Figure 5-1 is a simplified block diagram of the Timer0  
module.  
Additional information on timer modules is available in  
the PIC® Mid-Range Reference Manual (DS33023).  
The prescaler is not readable or writable.  
The PSA and PS2:PS0 bits (OPTION_REG<3:0>)  
determine the prescaler assignment and prescale ratio.  
5.1  
Timer0 Operation  
Timer0 can operate as a timer or as a counter.  
Clearing bit PSA will assign the prescaler to the Timer0  
module. When the prescaler is assigned to the Timer0  
module, prescale values of 1:2, 1:4, ..., 1:256 are  
selectable.  
Timer mode is selected by clearing bit T0CS  
(OPTION_REG<5>). In Timer mode, the Timer0 mod-  
ule will increment every instruction cycle (without pres-  
caler). If the TMR0 register is written, the increment is  
inhibited for the following two instruction cycles. The  
user can work around this by writing an adjusted value  
to the TMR0 register.  
Setting bit PSA will assign the prescaler to the Watchdog  
Timer (WDT). When the prescaler is assigned to the  
WDT, prescale values of 1:1, 1:2, ..., 1:128 are selectable.  
When assigned to the Timer0 module, all instructions  
writing to the TMR0 register (e.g., CLRF 1, MOVWF 1,  
BSF 1,etc.) will clear the prescaler. When assigned to  
WDT, a CLRWDT instruction will clear the prescaler  
along with the WDT.  
Counter mode is selected by setting bit T0CS  
(OPTION_REG<5>). In Counter mode, Timer0 will  
increment, either on every rising or falling edge of pin  
RA4/T0CKI. The incrementing edge is determined by  
the Timer0 Source Edge Select bit, T0SE  
(OPTION_REG<4>). Clearing bit T0SE selects the ris-  
ing edge. Restrictions on the external clock input are  
discussed below.  
Note: Writing to TMR0 when the prescaler is  
assigned to Timer0 will clear the prescaler  
count, but will not change the prescaler  
assignment.  
When an external clock input is used for Timer0, it must  
meet certain requirements. The requirements ensure  
the external clock can be synchronized with the internal  
phase clock (TOSC). Also, there is a delay in the actual  
incrementing of Timer0 after synchronization.  
FIGURE 5-1:  
TIMER0 BLOCK DIAGRAM  
Data Bus  
FOSC/4  
0
1
PSOUT  
8
1
0
Sync with  
Internal  
Clocks  
TMR0  
Programmable  
Prescaler  
RA4/T0CKI  
pin  
PSOUT  
(2 Cycle Delay)  
T0SE  
3
Set Interrupt  
Flag bit T0IF  
on Overflow  
PS2, PS1, PS0  
PSA  
T0CS  
Note 1: T0CS, T0SE, PSA, PS2:PS0 (OPTION_REG<5:0>).  
2: The prescaler is shared with Watchdog Timer (refer to Figure 5-2 for detailed block diagram).  
2001-2013 Microchip Technology Inc.  
DS35007C-page 19  
PIC16F84A  
5.2.1  
SWITCHING PRESCALER  
ASSIGNMENT  
5.3  
Timer0 Interrupt  
The TMR0 interrupt is generated when the TMR0 reg-  
ister overflows from FFh to 00h. This overflow sets bit  
T0IF (INTCON<2>). The interrupt can be masked by  
clearing bit T0IE (INTCON<5>). Bit T0IF must be  
cleared in software by the Timer0 module Interrupt Ser-  
vice Routine before re-enabling this interrupt. The  
TMR0 interrupt cannot awaken the processor from  
SLEEP since the timer is shut-off during SLEEP.  
The prescaler assignment is fully under software con-  
trol (i.e., it can be changed “on the fly” during program  
execution).  
Note: To avoid an unintended device RESET, a  
specific instruction sequence (shown in the  
PIC® Mid-Range Reference Manual,  
DS33023) must be executed when chang-  
ing the prescaler assignment from Timer0  
to the WDT. This sequence must be fol-  
lowed even if the WDT is disabled.  
FIGURE 5-2:  
BLOCK DIAGRAM OF THE TIMER0/WDT PRESCALER  
CLKOUT (= FOSC/4)  
Data Bus  
8
M
U
X
1
0
0
1
M
U
X
RA4/T0CKI  
pin  
SYNC  
TMR0 reg  
2
Cycles  
T0SE  
T0CS  
Set Flag bit T0IF  
on Overflow  
PSA  
0
1
8-bit Prescaler  
M
U
X
Watchdog  
Timer  
8
8 - to - 1 MUX  
PS2:PS0  
PSA  
1
0
WDT Enable bit  
M U X  
PSA  
WDT  
Time-out  
Note: T0CS, T0SE, PSA, PS2:PS0 are (OPTION_REG<5:0>).  
TABLE 5-1:  
REGISTERS ASSOCIATED WITH TIMER0  
Value on  
POR,  
BOR  
Value on all  
other  
RESETS  
Address  
Name  
Bit 7  
Bit 6  
Bit 5  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
01h  
TMR0  
INTCON  
Timer0 Module Register  
GIE EEIE T0IE  
xxxx xxxx uuuu uuuu  
RBIF 0000 000x 0000 000u  
0Bh,8Bh  
81h  
INTE  
RBIE  
PSA  
T0IF  
PS2  
INTF  
PS1  
OPTION_REG RBPU INTEDG T0CS T0SE  
TRISA  
PS0  
1111 1111 1111 1111  
---1 1111 ---1 1111  
85h  
PORTA Data Direction Register  
Legend: x= unknown, u= unchanged, -= unimplemented locations read as '0'. Shaded cells are not used by Timer0.  
DS35007C-page 20  
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PIC16F84A  
the chip in RESET until the crystal oscillator is stable.  
The other is the Power-up Timer (PWRT), which pro-  
vides a fixed delay of 72 ms (nominal) on power-up  
only. This design keeps the device in RESET while the  
power supply stabilizes. With these two timers on-chip,  
most applications need no external RESET circuitry.  
6.0  
SPECIAL FEATURES OF THE  
CPU  
What sets  
a
microcontroller apart from other  
processors are special circuits to deal with the needs of  
real time applications. The PIC16F84A has a host of  
such features intended to maximize system reliability,  
minimize cost through elimination of external  
components, provide power saving operating modes  
and offer code protection. These features are:  
SLEEP mode offers a very low current power-down  
mode. The user can wake-up from SLEEP through  
external RESET, Watchdog Timer Time-out or through  
an interrupt. Several oscillator options are provided to  
allow the part to fit the application. The RC oscillator  
option saves system cost while the LP crystal option  
saves power. A set of configuration bits are used to  
select the various options.  
• OSC Selection  
• RESET  
- Power-on Reset (POR)  
- Power-up Timer (PWRT)  
- Oscillator Start-up Timer (OST)  
• Interrupts  
Additional information on special features is available  
in the PIC® Mid-Range Reference Manual (DS33023).  
• Watchdog Timer (WDT)  
• SLEEP  
6.1  
Configuration Bits  
The configuration bits can be programmed (read as '0'),  
or left unprogrammed (read as '1'), to select various  
device configurations. These bits are mapped in  
program memory location 2007h.  
• Code Protection  
• ID Locations  
• In-Circuit Serial Programming™ (ICSP™)  
The PIC16F84A has a Watchdog Timer which can be  
shut-off only through configuration bits. It runs off its  
own RC oscillator for added reliability. There are two  
timers that offer necessary delays on power-up. One is  
the Oscillator Start-up Timer (OST), intended to keep  
Address 2007h is beyond the user program memory  
space and it belongs to the special test/configuration  
memory space (2000h - 3FFFh). This space can only  
be accessed during programming.  
REGISTER 6-1:  
PIC16F84A CONFIGURATION WORD  
R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u R/P-u  
R/P-u R/P-u  
R/P-u  
CP  
CP  
CP  
CP  
CP  
CP  
CP  
CP  
CP  
CP PWRTE WDTE F0SC1 F0SC0  
bit0  
bit13  
bit 13-4  
bit 3  
CP: Code Protection bit  
1= Code protection disabled  
0= All program memory is code protected  
PWRTE: Power-up Timer Enable bit  
1= Power-up Timer is disabled  
0= Power-up Timer is enabled  
bit 2  
WDTE: Watchdog Timer Enable bit  
1= WDT enabled  
0= WDT disabled  
bit 1-0  
FOSC1:FOSC0: Oscillator Selection bits  
11= RC oscillator  
10= HS oscillator  
01= XT oscillator  
00= LP oscillator  
2001-2013 Microchip Technology Inc.  
DS35007C-page 21  
PIC16F84A  
FIGURE 6-2:  
EXTERNAL CLOCK INPUT  
OPERATION (HS, XT OR  
LP OSC  
6.2  
Oscillator Configurations  
OSCILLATOR TYPES  
6.2.1  
CONFIGURATION)  
The PIC16F84A can be operated in four different  
oscillator modes. The user can program two  
configuration bits (FOSC1 and FOSC0) to select one of  
these four modes:  
OSC1  
Clock from  
Ext. System  
PIC16FXX  
• LP  
• XT  
• HS  
• RC  
Low Power Crystal  
Open  
OSC2  
Crystal/Resonator  
High Speed Crystal/Resonator  
Resistor/Capacitor  
TABLE 6-1:  
CAPACITOR SELECTION FOR  
CERAMIC RESONATORS  
6.2.2  
CRYSTAL OSCILLATOR/CERAMIC  
RESONATORS  
Ranges Tested:  
Mode  
In XT, LP, or HS modes, a crystal or ceramic resonator  
is connected to the OSC1/CLKIN and OSC2/CLKOUT  
pins to establish oscillation (Figure 6-1).  
Freq  
OSC1/C1  
OSC2/C2  
XT  
455 kHz  
2.0 MHz  
4.0 MHz  
47 - 100 pF 47 - 100 pF  
15 - 33 pF 15 - 33 pF  
15 - 33 pF 15 - 33 pF  
FIGURE 6-1:  
CRYSTAL/CERAMIC  
RESONATOROPERATION  
(HS, XT OR LP OSC  
CONFIGURATION)  
HS  
8.0 MHz  
15 - 33 pF 15 - 33 pF  
15 - 33 pF 15 - 33 pF  
10.0 MHz  
Note: Recommended values of C1 and C2 are  
identical to the ranges tested in this table.  
Higher capacitance increases the stability  
of the oscillator, but also increases the  
start-up time. These values are for design  
guidance only. Since each resonator has  
its own characteristics, the user should  
consult the resonator manufacturer for the  
appropriate values of external compo-  
nents.  
C1(1)  
OSC1  
To  
Internal  
Logic  
XTAL  
(3)  
RF  
OSC2  
SLEEP  
PIC16FXX  
(2)  
RS  
C2(1)  
Note 1: See Table 6-1 for recommended values  
of C1 and C2.  
2: A series resistor (RS) may be required  
Note: When using resonators with frequencies  
above 3.5 MHz, the use of HS mode rather  
than XT mode, is recommended. HS mode  
may be used at any VDD for which the  
controller is rated.  
for AT strip cut crystals.  
The PIC16F84A oscillator design requires the use of a  
parallel cut crystal. Use of a series cut crystal may give  
a
frequency out of the crystal manufacturers  
specifications. When in XT, LP, or HS modes, the  
device can have an external clock source to drive the  
OSC1/CLKIN pin (Figure 6-2).  
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PIC16F84A  
TABLE 6-2:  
CAPACITOR SELECTION  
6.2.3  
RC OSCILLATOR  
FOR CRYSTAL OSCILLATOR  
For timing insensitive applications, the RC device  
option offers additional cost savings. The RC oscillator  
frequency is a function of the supply voltage, the  
resistor (REXT) values, capacitor (CEXT) values, and  
the operating temperature. In addition to this, the oscil-  
lator frequency will vary from unit to unit due to normal  
process parameter variation. Furthermore, the  
difference in lead frame capacitance between package  
types also affects the oscillation frequency, especially  
for low CEXT values. The user needs to take into  
account variation, due to tolerance of the external  
R and C components. Figure 6-3 shows how an R/C  
combination is connected to the PIC16F84A.  
Mode  
Freq  
OSC1/C1  
OSC2/C2  
LP  
32 kHz  
200 kHz  
68 - 100 pF  
15 - 33 pF  
68 - 100 pF  
15 - 33 pF  
XT  
HS  
100 kHz  
2 MHz  
4 MHz  
100 - 150 pF 100 - 150 pF  
15 - 33 pF  
15 - 33 pF  
15 - 33 pF  
15 - 33 pF  
4 MHz  
20 MHz  
15 - 33 pF  
15 - 33 pF  
15 - 33 pF  
15 - 33 pF  
Note: Higher capacitance increases the stability  
of the oscillator, but also increases the  
start-up time. These values are for design  
guidance only. Rs may be required in HS  
mode, as well as XT mode, to avoid over-  
driving crystals with low drive level specifi-  
cation. Since each crystal has its own  
characteristics, the user should consult the  
crystal manufacturer for appropriate  
values of external components.  
FIGURE 6-3:  
RC OSCILLATOR MODE  
VDD  
REXT  
Internal  
OSC1  
Clock  
For VDD > 4.5V, C1 = C2 30 pF is recom-  
mended.  
CEXT  
VSS  
PIC16FXX  
OSC2/CLKOUT  
FOSC/4  
Recommended values: 5 k  REXT 100 k  
CEXT > 20pF  
2001-2013 Microchip Technology Inc.  
DS35007C-page 23  
PIC16F84A  
Some registers are not affected in any RESET condition;  
their status is unknown on a POR and unchanged in any  
other RESET. Most other registers are reset to a “RESET  
state” on POR, MCLR or WDT Reset during normal oper-  
ation and on MCLR during SLEEP. They are not affected  
by a WDT Reset during SLEEP, since this RESET is  
viewed as the resumption of normal operation.  
6.3  
RESET  
The PIC16F84A differentiates between various kinds  
of RESET:  
• Power-on Reset (POR)  
• MCLR during normal operation  
• MCLR during SLEEP  
Table 6-3 gives a description of RESET conditions for  
the program counter (PC) and the STATUS register.  
Table 6-4 gives a full description of RESET states for all  
registers.  
• WDT Reset (during normal operation)  
• WDT Wake-up (during SLEEP)  
Figure 6-4 shows a simplified block diagram of the  
On-Chip RESET Circuit. The MCLR Reset path has a  
noise filter to ignore small pulses. The electrical speci-  
fications state the pulse width requirements for the  
MCLR pin.  
The TO and PD bits are set or cleared differently in dif-  
ferent RESET situations (Section 6.7). These bits are  
used in software to determine the nature of the RESET.  
FIGURE 6-4:  
SIMPLIFIED BLOCK DIAGRAM OF ON-CHIP RESET CIRCUIT  
External Reset  
MCLR  
SLEEP  
WDT  
Time-out  
Reset  
WDT  
Module  
VDD Rise  
Detect  
S
Power-on Reset  
VDD  
OST/PWRT  
OST  
10-bit Ripple Counter  
Chip_Reset  
Q
R
OSC1/  
CLKIN  
PWRT  
10-bit Ripple Counter  
On-Chip  
(1)  
RC Osc  
See Table 6-5  
Enable PWRT  
Enable OST  
Note 1: This is a separate oscillator from the RC oscillator of the CLKIN pin.  
2: See Table 6-5.  
TABLE 6-3:  
RESET CONDITION FOR PROGRAM COUNTER AND THE STATUS REGISTER  
Condition  
Program Counter  
STATUS Register  
0001 1xxx  
000u uuuu  
0001 0uuu  
0000 1uuu  
uuu0 0uuu  
uuu1 0uuu  
Power-on Reset  
000h  
000h  
MCLR during normal operation  
MCLR during SLEEP  
000h  
WDT Reset (during normal operation)  
WDT Wake-up  
000h  
PC + 1  
PC + 1(1)  
Interrupt wake-up from SLEEP  
Legend: u= unchanged, x= unknown  
Note 1: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector (0004h).  
DS35007C-page 24  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
TABLE 6-4:  
Register  
RESET CONDITIONS FOR ALL REGISTERS  
MCLR during:  
– normal operation  
– SLEEP  
Wake-up from SLEEP:  
– through interrupt  
Address  
Power-on Reset  
WDT Reset during  
normal operation  
– through WDT Time-out  
W
xxxx xxxx  
---- ----  
xxxx xxxx  
0000 0000  
0001 1xxx  
xxxx xxxx  
---x xxxx  
xxxx xxxx  
xxxx xxxx  
xxxx xxxx  
---0 0000  
0000 000x  
---- ----  
1111 1111  
0000 0000  
0001 1xxx  
xxxx xxxx  
---1 1111  
1111 1111  
---0 x000  
---- ----  
---0 0000  
0000 000x  
uuuu uuuu  
---- ----  
uuuu uuuu  
0000 0000  
000q quuu(3)  
uuuu uuuu  
---u uuuu  
uuuu uuuu  
uuuu uuuu  
uuuu uuuu  
---0 0000  
0000 000u  
---- ----  
1111 1111  
0000 0000  
000q quuu(3)  
uuuu uuuu  
---1 1111  
1111 1111  
---0 q000  
---- ----  
---0 0000  
0000 000u  
uuuu uuuu  
---- ----  
uuuu uuuu  
PC + 1(2)  
INDF  
00h  
01h  
02h  
03h  
04h  
05h  
06h  
08h  
09h  
0Ah  
0Bh  
80h  
81h  
82h  
83h  
84h  
85h  
86h  
88h  
89h  
8Ah  
8Bh  
TMR0  
PCL  
STATUS  
uuuq quuu(3)  
uuuu uuuu  
---u uuuu  
uuuu uuuu  
uuuu uuuu  
uuuu uuuu  
---u uuuu  
uuuu uuuu(1)  
---- ----  
uuuu uuuu  
PC + 1(2)  
uuuq quuu(3)  
uuuu uuuu  
---u uuuu  
uuuu uuuu  
---0 uuuu  
---- ----  
---u uuuu  
uuuu uuuu(1)  
FSR  
PORTA(4)  
PORTB(5)  
EEDATA  
EEADR  
PCLATH  
INTCON  
INDF  
OPTION_REG  
PCL  
STATUS  
FSR  
TRISA  
TRISB  
EECON1  
EECON2  
PCLATH  
INTCON  
Legend: u= unchanged, x= unknown, -= unimplemented bit, read as '0', q= value depends on condition  
Note 1: One or more bits in INTCON will be affected (to cause wake-up).  
2: When the wake-up is due to an interrupt and the GIE bit is set, the PC is loaded with the interrupt vector  
(0004h).  
3: Table 6-3 lists the RESET value for each specific condition.  
4: On any device RESET, these pins are configured as inputs.  
5: This is the value that will be in the port output latch.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 25  
PIC16F84A  
6.4  
Power-on Reset (POR)  
6.6  
Oscillator Start-up Timer (OST)  
A Power-on Reset pulse is generated on-chip when  
VDD rise is detected (in the range of 1.2V - 1.7V). To  
take advantage of the POR, just tie the MCLR pin  
directly (or through a resistor) to VDD. This will  
eliminate external RC components usually needed to  
create Power-on Reset. A minimum rise time for VDD  
must be met for this to operate properly. See Electrical  
Specifications for details.  
The Oscillator Start-up Timer (OST) provides a 1024  
oscillator cycle delay (from OSC1 input) after the  
PWRT delay ends (Figure 6-6, Figure 6-7, Figure 6-8  
and Figure 6-9). This ensures the crystal oscillator or  
resonator has started and stabilized.  
The OST time-out (TOST) is invoked only for XT, LP and  
HS modes and only on Power-on Reset or wake-up  
from SLEEP.  
When the device starts normal operation (exits the  
RESET condition), device operating parameters (volt-  
age, frequency, temperature, etc.) must be met to  
ensure operation. If these conditions are not met, the  
device must be held in RESET until the operating con-  
ditions are met.  
When VDD rises very slowly, it is possible that the  
TPWRT time-out and TOST time-out will expire before  
VDD has reached its final value. In this case  
(Figure 6-9), an external Power-on Reset circuit may  
be necessary (Figure 6-5).  
For additional information, refer to Application Note  
AN607, "Power-up Trouble Shooting."  
FIGURE 6-5:  
EXTERNAL POWER-ON  
RESET CIRCUIT (FOR  
SLOW VDD POWER-UP)  
The POR circuit does not produce an internal RESET  
when VDD declines.  
VDD  
D
VDD  
6.5  
Power-up Timer (PWRT)  
The Power-up Timer (PWRT) provides a fixed 72 ms  
nominal time-out (TPWRT) from POR (Figures 6-6  
through 6-9). The Power-up Timer operates on an  
internal RC oscillator. The chip is kept in RESET as  
long as the PWRT is active. The PWRT delay allows  
the VDD to rise to an acceptable level (possible excep-  
tion shown in Figure 6-9).  
R
R1  
MCLR  
PIC16FXX  
C
Note 1: External Power-on Reset circuit is required  
only if VDD power-up rate is too slow. The  
A configuration bit, PWRTE, can enable/disable the  
PWRT. See Register 6-1 for the operation of the  
PWRTE bit for a particular device.  
diode  
D helps discharge the capacitor  
quickly when VDD powers down.  
2: R < 40 kis recommended to make sure  
that voltage drop across R does not exceed  
0.2V (max leakage current spec on MCLR  
pin is 5 A). A larger voltage drop will  
degrade VIH level on the MCLR pin.  
The power-up time delay TPWRT will vary from chip to  
chip due to VDD, temperature, and process variation.  
See DC parameters for details.  
3: R1 = 100to 1 kwill limit any current flow-  
ing into MCLR from external capacitor C, in  
the event of a MCLR pin breakdown due to  
ESD or EOS.  
DS35007C-page 26  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 6-6:  
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 1  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
OST TIME-OUT  
TOST  
INTERNAL RESET  
FIGURE 6-7:  
TIME-OUT SEQUENCE ON POWER-UP (MCLR NOT TIED TO VDD): CASE 2  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
OST TIME-OUT  
TOST  
INTERNAL RESET  
FIGURE 6-8:  
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD): FAST VDD RISE  
TIME  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
OST TIME-OUT  
TOST  
INTERNAL RESET  
2001-2013 Microchip Technology Inc.  
DS35007C-page 27  
PIC16F84A  
FIGURE 6-9:  
TIME-OUT SEQUENCE ON POWER-UP (MCLR TIED TO VDD):  
SLOW VDD RISE TIME  
V1  
VDD  
MCLR  
INTERNAL POR  
TPWRT  
PWRT TIME-OUT  
OST TIME-OUT  
TOST  
INTERNAL RESET  
When VDD rises very slowly, it is possible that the TPWRT time-out and TOST time-out will expire before VDD  
has reached its final value. In this example, the chip will reset properly if, and only if, V1 VDD min.  
Since the time-outs occur from the POR pulse, if MCLR  
is kept low long enough, the time-outs will expire. Then  
bringing MCLR high, execution will begin immediately  
6.7  
Time-out Sequence and  
Power-down Status Bits (TO/PD)  
On power-up (Figures 6-6 through 6-9), the time-out  
sequence is as follows:  
(Figure 6-6). This is useful for testing purposes or to  
synchronize more than one PIC16F84A device when  
operating in parallel.  
1. PWRT time-out is invoked after a POR has  
expired.  
Table 6-6 shows the significance of the TO and PD bits.  
Table 6-3 lists the RESET conditions for some special  
registers, while Table 6-4 lists the RESET conditions  
for all the registers.  
2. Then, the OST is activated.  
The total time-out will vary based on oscillator configu-  
ration and PWRTE configuration bit status. For exam-  
ple, in RC mode with the PWRT disabled, there will be  
no time-out at all.  
TABLE 6-6:  
STATUS BITS AND THEIR  
SIGNIFICANCE  
TABLE 6-5:  
TIME-OUT IN VARIOUS  
SITUATIONS  
TO PD  
Condition  
1
0
x
0
0
1
1
1
x
0
1
0
1
0
Power-on Reset  
Power-up  
Illegal, TO is set on POR  
Illegal, PD is set on POR  
WDT Reset (during normal operation)  
WDT Wake-up  
Wake-up  
Oscillator  
Configuration  
from  
PWRT  
Enabled  
PWRT  
Disabled  
SLEEP  
72 ms +  
1024TOSC  
XT, HS, LP  
RC  
1024TOSC 1024TOSC  
MCLR during normal operation  
MCLR during SLEEP or interrupt  
wake-up from SLEEP  
72 ms  
DS35007C-page 28  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
6.8.1  
INT INTERRUPT  
6.8  
Interrupts  
External interrupt on RB0/INT pin is edge triggered:  
either rising if INTEDG bit (OPTION_REG<6>) is set,  
or falling if INTEDG bit is clear. When a valid edge  
appears on the RB0/INT pin, the INTF bit  
(INTCON<1>) is set. This interrupt can be disabled by  
clearing control bit INTE (INTCON<4>). Flag bit INTF  
must be cleared in software via the Interrupt Service  
Routine before re-enabling this interrupt. The INT  
interrupt can wake the processor from SLEEP  
(Section 6.11) only if the INTE bit was set prior to going  
into SLEEP. The status of the GIE bit decides whether  
the processor branches to the interrupt vector  
following wake-up.  
The PIC16F84A has 4 sources of interrupt:  
• External interrupt RB0/INT pin  
• TMR0 overflow interrupt  
• PORTB change interrupts (pins RB7:RB4)  
• Data EEPROM write complete interrupt  
The interrupt control register (INTCON) records  
individual interrupt requests in flag bits. It also contains  
the individual and global interrupt enable bits.  
The global interrupt enable bit, GIE (INTCON<7>),  
enables (if set) all unmasked interrupts or disables (if  
cleared) all interrupts. Individual interrupts can be  
disabled through their corresponding enable bits in  
INTCON register. Bit GIE is cleared on RESET.  
6.8.2  
TMR0 INTERRUPT  
The “return from interrupt” instruction, RETFIE, exits  
interrupt routine as well as sets the GIE bit, which  
re-enables interrupts.  
An overflow (FFh 00h) in TMR0 will set flag bit T0IF  
(INTCON<2>). The interrupt can be enabled/disabled  
by setting/clearing enable bit T0IE (INTCON<5>)  
(Section 5.0).  
The RB0/INT pin interrupt, the RB port change interrupt  
and the TMR0 overflow interrupt flags are contained in  
the INTCON register.  
6.8.3  
PORTB INTERRUPT  
When an interrupt is responded to, the GIE bit is  
cleared to disable any further interrupt, the return  
address is pushed onto the stack and the PC is loaded  
with 0004h. For external interrupt events, such as the  
RB0/INT pin or PORTB change interrupt, the interrupt  
latency will be three to four instruction cycles. The  
exact latency depends when the interrupt event occurs.  
The latency is the same for both one and two cycle  
instructions. Once in the Interrupt Service Routine, the  
source(s) of the interrupt can be determined by polling  
the interrupt flag bits. The interrupt flag bit(s) must be  
cleared in software before re-enabling interrupts to  
avoid infinite interrupt requests.  
An input change on PORTB<7:4> sets flag bit RBIF  
(INTCON<0>). The interrupt can be enabled/disabled  
by setting/clearing enable bit RBIE (INTCON<3>)  
(Section 4.2).  
Note: For a change on the I/O pin to be  
recognized, the pulse width must be at  
least TCY wide.  
6.8.4  
DATA EEPROM INTERRUPT  
At the completion of a data EEPROM write cycle, flag  
bit EEIF (EECON1<4>) will be set. The interrupt can be  
enabled/disabled by setting/clearing enable bit EEIE  
(INTCON<6>) (Section 3.0).  
Note: Individual interrupt flag bits are set  
regardless of the status of their  
corresponding mask bit or the GIE bit.  
FIGURE 6-10:  
INTERRUPT LOGIC  
Wake-up  
(If in SLEEP mode)  
T0IF  
T0IE  
INTF  
INTE  
Interrupt to CPU  
RBIF  
RBIE  
EEIF  
EEIE  
GIE  
2001-2013 Microchip Technology Inc.  
DS35007C-page 29  
PIC16F84A  
Example 6-1 does the following:  
6.9  
Context Saving During Interrupts  
a) Stores the W register.  
During an interrupt, only the return PC value is saved  
on the stack. Typically, users wish to save key register  
values during an interrupt (e.g., W register and  
STATUS register). This is implemented in software.  
b) Stores the STATUS register in STATUS_TEMP.  
c) Executes the Interrupt Service Routine code.  
d) Restores the STATUS (and bank select bit)  
register.  
The code in Example 6-1 stores and restores the  
STATUS and W register’s values. The user defined  
registers, W_TEMP and STATUS_TEMP are the tem-  
porary storage locations for the W and STATUS  
registers values.  
e) Restores the W register.  
EXAMPLE 6-1:  
SAVING STATUS AND W REGISTERS IN RAM  
PUSH  
MOVWF  
W_TEMP  
; Copy W to TEMP register,  
SWAPF  
MOVWF  
:
STATUS,  
STATUS_TEMP  
W
; Swap status to be saved into W  
; Save status to STATUS_TEMP register  
:
ISR  
:
:
:
; Interrupt Service Routine  
; should configure Bank as required  
;
POP  
SWAPF  
STATUS_TEMP,W  
STATUS  
; Swap nibbles in STATUS_TEMP register  
; and place result into W  
; Move W into STATUS register  
; (sets bank to original state)  
; Swap nibbles in W_TEMP and place result in W_TEMP  
; Swap nibbles in W_TEMP and place result into W  
MOVWF  
SWAPF  
SWAPF  
W_TEMP,  
W_TEMP,  
F
W
6.10.1  
WDT PERIOD  
6.10 Watchdog Timer (WDT)  
The WDT has a nominal time-out period of 18 ms, (with  
no prescaler). The time-out periods vary with  
temperature, VDD and process variations from part to  
part (see DC specs). If longer time-out periods are  
desired, a prescaler with a division ratio of up to 1:128  
can be assigned to the WDT under software control by  
writing to the OPTION_REG register. Thus, time-out  
periods up to 2.3 seconds can be realized.  
The Watchdog Timer is a free running On-Chip RC  
Oscillator which does not require any external  
components. This RC oscillator is separate from the  
RC oscillator of the OSC1/CLKIN pin. That means that  
the WDT will run even if the clock on the OSC1/CLKIN  
and OSC2/CLKOUT pins of the device has been  
stopped, for example, by execution of a SLEEP  
instruction. During normal operation, a WDT time-out  
generates a device RESET. If the device is in SLEEP  
mode, a WDT wake-up causes the device to wake-up  
and continue with normal operation. The WDT can be  
permanently disabled by programming configuration bit  
WDTE as a '0' (Section 6.1).  
The CLRWDT and SLEEP instructions clear the WDT  
and the postscaler (if assigned to the WDT) and pre-  
vent it from timing out and generating a device  
RESETcondition.  
The TO bit in the STATUS register will be cleared upon  
a WDT time-out.  
DS35007C-page 30  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
6.10.2  
WDT PROGRAMMING  
CONSIDERATIONS  
It should also be taken into account that under worst  
case conditions (VDD = Min., Temperature = Max., Max.  
WDT Prescaler), it may take several seconds before a  
WDT time-out occurs.  
FIGURE 6-11:  
WATCHDOG TIMER BLOCK DIAGRAM  
From TMR0 Clock Source  
(Figure 5-2)  
0
M
Postscaler  
8
1
U
WDT Timer  
X
PS2:PS0  
8 - to -1 MUX  
PSA  
WDT  
Enable Bit  
To TMR0 (Figure 5-2)  
1
0
MUX  
PSA  
WDT  
Time-out  
Note:  
PSA and PS2:PS0 are bits in the OPTION_REG register.  
TABLE 6-7:  
SUMMARY OF REGISTERS ASSOCIATED WITH THE WATCHDOG TIMER  
Value on Value on all  
Addr  
Name  
Bit 7  
(2)  
Bit 6  
(2)  
Bit 5  
(2)  
Bit 4  
Bit 3  
Bit 2  
Bit 1  
Bit 0  
Power-on  
Reset  
other  
RESETS  
(1)  
2007h Config. bits  
(2)  
PWRTE  
PSA  
WDTE FOSC1 FOSC0  
PS2 PS1 PS0  
(2)  
81h  
OPTION_REG RBPU INTEDG T0CS  
T0SE  
1111 1111 1111 1111  
Legend: x= unknown. Shaded cells are not used by the WDT.  
Note 1: See Register 6-1 for operation of the PWRTE bit.  
2: See Register 6-1 and Section 6.12 for operation of the code and data protection bits.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 31  
PIC16F84A  
6.11.2  
WAKE-UP FROM SLEEP  
6.11 Power-down Mode (SLEEP)  
The device can wake-up from SLEEP through one of  
the following events:  
A device may be powered down (SLEEP) and later  
powered up (wake-up from SLEEP).  
1. External RESET input on MCLR pin.  
2. WDT wake-up (if WDT was enabled).  
6.11.1  
SLEEP  
The Power-down mode is entered by executing the  
SLEEPinstruction.  
3. Interrupt from RB0/INT pin, RB port change, or  
data EEPROM write complete.  
If enabled, the Watchdog Timer is cleared (but keeps  
running), the PD bit (STATUS<3>) is cleared, the TO bit  
(STATUS<4>) is set, and the oscillator driver is turned  
off. The I/O ports maintain the status they had before  
the SLEEPinstruction was executed (driving high, low,  
or hi-impedance).  
Peripherals cannot generate interrupts during SLEEP,  
since no on-chip Q clocks are present.  
The first event (MCLR Reset) will cause a device  
RESET. The two latter events are considered a contin-  
uation of program execution. The TO and PD bits can  
be used to determine the cause of a device RESET.  
The PD bit, which is set on power-up, is cleared when  
SLEEP is invoked. The TO bit is cleared if a WDT  
time-out occurred (and caused wake-up).  
For the lowest current consumption in SLEEP mode,  
place all I/O pins at either VDD or VSS, with no external  
circuitry drawing current from the I/O pins, and disable  
external clocks. I/O pins that are hi-impedance inputs  
should be pulled high or low externally to avoid switch-  
ing currents caused by floating inputs. The T0CKI input  
should also be at VDD or VSS. The contribution from  
on-chip pull-ups on PORTB should be considered.  
While the SLEEPinstruction is being executed, the next  
instruction (PC + 1) is pre-fetched. For the device to  
wake-up through an interrupt event, the corresponding  
interrupt enable bit must be set (enabled). Wake-up  
occurs regardless of the state of the GIE bit. If the GIE  
bit is clear (disabled), the device continues execution at  
the instruction after the SLEEPinstruction. If the GIE bit  
is set (enabled), the device executes the instruction  
after the SLEEP instruction and then branches to the  
interrupt address (0004h). In cases where the  
execution of the instruction following SLEEP is not  
desirable, the user should have a NOP after the  
SLEEPinstruction.  
The MCLR pin must be at a logic high level (VIHMC).  
It should be noted that a RESET generated by a WDT  
time-out does not drive the MCLR pin low.  
FIGURE 6-12:  
WAKE-UP FROM SLEEP THROUGH INTERRUPT  
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1  
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4  
OSC1  
CLKOUT(4)  
INT pin  
(2)  
TOST  
INTF Flag  
(INTCON<1>)  
Interrupt Latency  
(Note 2)  
GIE bit  
(INTCON<7>)  
Processor in  
SLEEP  
INSTRUCTION FLOW  
PC  
PC+2  
PC + 2  
PC  
PC+1  
PC+2  
0004h  
0005h  
Instruction  
Inst(0004h)  
Inst(PC + 1)  
Inst(PC + 2)  
Inst(PC + 1)  
Inst(PC) = SLEEP  
Inst(PC - 1)  
Inst(0005h)  
Inst(0004h)  
Fetched  
Instruction  
Executed  
Dummy cycle  
SLEEP  
Dummy cycle  
Note 1: XT, HS, or LP oscillator mode assumed.  
2: TOST = 1024TOSC (drawing not to scale). This delay will not be there for RC osc mode.  
3: GIE = '1' assumed. In this case after wake-up, the processor jumps to the interrupt routine. If GIE = '0', execution will continue in-line.  
4: CLKOUT is not available in these osc modes, but shown here for timing reference.  
DS35007C-page 32  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
6.11.3  
WAKE-UP USING INTERRUPTS  
6.12 Program Verification/Code  
Protection  
When global interrupts are disabled (GIE cleared) and  
any interrupt source has both its interrupt enable bit  
and interrupt flag bit set, one of the following will occur:  
If the code protection bit(s) have not been pro-  
grammed, the on-chip program memory can be read  
out for verification purposes.  
• If the interrupt occurs before the execution of a  
SLEEPinstruction, the SLEEPinstruction will com-  
plete as a NOP. Therefore, the WDT and WDT  
postscaler will not be cleared, the TO bit will not  
be set and PD bits will not be cleared.  
6.13 ID Locations  
Four memory locations (2000h - 2004h) are designated  
as ID locations to store checksum or other code  
identification numbers. These locations are not  
accessible during normal execution but are readable  
and writable only during program/verify. Only the  
four Least Significant bits of ID location are usable.  
• If the interrupt occurs during or after the execu-  
tion of a SLEEPinstruction, the device will imme-  
diately wake-up from SLEEP. The SLEEP  
instruction will be completely executed before the  
wake-up. Therefore, the WDT and WDT  
postscaler will be cleared, the TO bit will be set  
and the PD bit will be cleared.  
6.14 In-Circuit Serial Programming  
PIC16F84A microcontrollers can be serially  
programmed while in the end application circuit. This is  
simply done with two lines for clock and data, and three  
other lines for power, ground, and the programming  
voltage. Customers can manufacture boards with  
unprogrammed devices, and then program the  
microcontroller just before shipping the product,  
allowing the most recent firmware or custom firmware  
to be programmed.  
Even if the flag bits were checked before executing a  
SLEEP instruction, it may be possible for flag bits to  
become set before the SLEEPinstruction completes. To  
determine whether a SLEEPinstruction executed, test  
the PD bit. If the PD bit is set, the SLEEP instruction  
was executed as a NOP.  
To ensure that the WDT is cleared, a CLRWDTinstruc-  
tion should be executed before a SLEEPinstruction.  
For complete details of Serial Programming, please  
refer to the In-Circuit Serial Programming™ (ICSP™)  
Guide, (DS30277).  
2001-2013 Microchip Technology Inc.  
DS35007C-page 33  
PIC16F84A  
NOTES:  
DS35007C-page 34  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
All instructions are executed within one single instruc-  
tion cycle, unless a conditional test is true or the pro-  
gram counter is changed as a result of an instruction.  
In this case, the execution takes two instruction cycles  
with the second cycle executed as a NOP. One instruc-  
tion cycle consists of four oscillator periods. Thus, for  
an oscillator frequency of 4 MHz, the normal instruction  
execution time is 1 s. If a conditional test is true or the  
program counter is changed as a result of an instruc-  
tion, the instruction execution time is 2 s.  
7.0  
INSTRUCTION SET SUMMARY  
Each PIC16CXX instruction is a 14-bit word, divided  
into an OPCODE which specifies the instruction type  
and one or more operands which further specify the  
operation of the instruction. The PIC16CXX instruction  
set summary in Table 7-2 lists byte-oriented, bit-ori-  
ented, and literal and control operations. Table 7-1  
shows the opcode field descriptions.  
For byte-oriented instructions, 'f' represents a file reg-  
ister designator and 'd' represents a destination desig-  
nator. The file register designator specifies which file  
register is to be used by the instruction.  
Table 7-2 lists the instructions recognized by the  
MPASM™ Assembler.  
Figure 7-1 shows the general formats that the instruc-  
tions can have.  
The destination designator specifies where the result of  
the operation is to be placed. If 'd' is zero, the result is  
placed in the W register. If 'd' is one, the result is placed  
in the file register specified in the instruction.  
Note: To maintain upward compatibility with  
future PIC16CXX products, do not use the  
OPTIONand TRISinstructions.  
For bit-oriented instructions, 'b' represents a bit field  
designator which selects the number of the bit affected  
by the operation, while 'f' represents the address of the  
file in which the bit is located.  
All examples use the following format to represent a  
hexadecimal number:  
0xhh  
For literal and control operations, 'k' represents an  
where h signifies a hexadecimal digit.  
eight or eleven bit constant or literal value.  
FIGURE 7-1:  
GENERAL FORMAT FOR  
INSTRUCTIONS  
TABLE 7-1:  
OPCODE FIELD  
DESCRIPTIONS  
Byte-oriented file register operations  
13  
8
7
6
0
Field  
Description  
OPCODE  
d
f (FILE #)  
f
W
b
k
x
Register file address (0x00 to 0x7F)  
Working register (accumulator)  
d = 0 for destination W  
d = 1 for destination f  
f = 7-bit file register address  
Bit address within an 8-bit file register  
Literal field, constant data or label  
Bit-oriented file register operations  
13 10 9  
b (BIT #)  
7
6
0
Don't care location (= 0or 1)  
OPCODE  
f (FILE #)  
The assembler will generate code with x = 0.  
It is the recommended form of use for compat-  
ibility with all Microchip software tools.  
b = 3-bit bit address  
f = 7-bit file register address  
d
Destination select; d = 0: store result in W,  
d = 1: store result in file register f.  
Default is d = 1  
Literal and control operations  
General  
PC  
TO  
PD  
Program Counter  
Time-out bit  
13  
8
7
0
0
OPCODE  
k (literal)  
Power-down bit  
k = 8-bit immediate value  
The instruction set is highly orthogonal and is grouped  
into three basic categories:  
CALLand GOTOinstructions only  
13 11 10  
OPCODE  
k = 11-bit immediate value  
Byte-oriented operations  
Bit-oriented operations  
k (literal)  
Literal and control operations  
A description of each instruction is available in the PIC®  
Mid-Range Reference Manual (DS33023).  
2001-2013 Microchip Technology Inc.  
DS35007C-page 35  
PIC16F84A  
TABLE 7-2:  
PIC16CXXX INSTRUCTION SET  
14-Bit Opcode  
Mnemonic,  
Operands  
Status  
Affected  
Description  
Cycles  
Notes  
MSb  
LSb  
BYTE-ORIENTED FILE REGISTER OPERATIONS  
ADDWF  
ANDWF  
CLRF  
CLRW  
COMF  
DECF  
f, d  
f, d  
f
Add W and f  
AND W with f  
Clear f  
Clear W  
Complement f  
Decrement f  
Decrement f, Skip if 0  
Increment f  
Increment f, Skip if 0  
Inclusive OR W with f  
Move f  
1
1
1
1
1
1
1 (2)  
1
1 (2)  
1
1
1
1
1
1
1
1
1
00 0111 dfff ffff C,DC,Z  
1,2  
1,2  
2
00 0101 dfff ffff  
00 0001 lfff ffff  
00 0001 0xxx xxxx  
00 1001 dfff ffff  
00 0011 dfff ffff  
00 1011 dfff ffff  
00 1010 dfff ffff  
00 1111 dfff ffff  
00 0100 dfff ffff  
00 1000 dfff ffff  
00 0000 lfff ffff  
00 0000 0xx0 0000  
00 1101 dfff ffff  
00 1100 dfff ffff  
Z
Z
Z
Z
Z
-
f, d  
f, d  
f, d  
f, d  
f, d  
f, d  
f, d  
f
1,2  
1,2  
1,2,3  
1,2  
1,2,3  
1,2  
1,2  
DECFSZ  
INCF  
Z
INCFSZ  
IORWF  
MOVF  
MOVWF  
NOP  
RLF  
RRF  
SUBWF  
SWAPF  
XORWF  
Z
Z
Move W to f  
No Operation  
-
f, d  
f, d  
f, d  
f, d  
f, d  
Rotate Left f through Carry  
Rotate Right f through Carry  
Subtract W from f  
Swap nibbles in f  
Exclusive OR W with f  
C
C
1,2  
1,2  
1,2  
1,2  
1,2  
00 0010 dfff ffff C,DC,Z  
00 1110 dfff ffff  
00 0110 dfff ffff  
Z
BIT-ORIENTED FILE REGISTER OPERATIONS  
BCF  
BSF  
BTFSC  
BTFSS  
f, b  
f, b  
f, b  
f, b  
Bit Clear f  
Bit Set f  
Bit Test f, Skip if Clear  
Bit Test f, Skip if Set  
1
1
1 (2)  
1 (2)  
01 00bb bfff ffff  
1,2  
1,2  
3
01 01bb bfff ffff  
01 10bb bfff ffff  
01 11bb bfff ffff  
3
LITERAL AND CONTROL OPERATIONS  
ADDLW  
ANDLW  
CALL  
CLRWDT  
GOTO  
IORLW  
MOVLW  
RETFIE  
RETLW  
RETURN  
SLEEP  
SUBLW  
XORLW  
k
k
k
-
k
k
k
-
k
-
-
k
k
Add literal and W  
AND literal with W  
Call subroutine  
Clear Watchdog Timer  
Go to address  
1
1
2
1
2
1
1
2
2
2
1
1
1
11 111x kkkk kkkk C,DC,Z  
11 1001 kkkk kkkk  
10 0kkk kkkk kkkk  
00 0000 0110 0100  
10 1kkk kkkk kkkk  
11 1000 kkkk kkkk  
11 00xx kkkk kkkk  
00 0000 0000 1001  
11 01xx kkkk kkkk  
00 0000 0000 1000  
00 0000 0110 0011  
Z
TO,PD  
Z
Inclusive OR literal with W  
Move literal to W  
Return from interrupt  
Return with literal in W  
Return from Subroutine  
Go into standby mode  
Subtract W from literal  
Exclusive OR literal with W  
TO,PD  
11 110x kkkk kkkk C,DC,Z  
11 1010 kkkk kkkk  
Z
Note 1: When an I/O register is modified as a function of itself ( e.g., MOVF PORTB, 1), the value used will be that value present  
on the pins themselves. For example, if the data latch is '1' for a pin configured as input and is driven low by an external  
device, the data will be written back with a '0'.  
2: If this instruction is executed on the TMR0 register (and, where applicable, d = 1), the prescaler will be cleared if  
assigned to the Timer0 Module.  
3: If Program Counter (PC) is modified or a conditional test is true, the instruction requires two cycles. The second cycle is  
executed as a NOP.  
Note: Additional information on the mid-range instruction set is available in the PIC® Mid-Range MCU Family Ref-  
erence Manual (DS33023).  
DS35007C-page 36  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
7.1  
Instruction Descriptions  
ADDLW  
Add Literal and W  
BCF  
Bit Clear f  
Syntax:  
[label] ADDLW  
0 k 255  
k
Syntax:  
[label] BCF f,b  
Operands:  
Operation:  
Status Affected:  
Description:  
Operands:  
0 f 127  
0 b 7  
(W) + k (W)  
C, DC, Z  
Operation:  
0 (f<b>)  
Status Affected:  
Description:  
None  
The contents of the W register  
are added to the eight-bit literal 'k'  
and the result is placed in the W  
register.  
Bit 'b' in register 'f' is cleared.  
BSF  
Bit Set f  
ADDWF  
Add W and f  
Syntax:  
[label] BSF f,b  
Syntax:  
[label] ADDWF f,d  
Operands:  
0 f 127  
0 b 7  
Operands:  
0 f 127  
d   
Operation:  
1 (f<b>)  
Operation:  
(W) + (f) (destination)  
Status Affected:  
Description:  
None  
Status Affected: C, DC, Z  
Bit 'b' in register 'f' is set.  
Description:  
Add the contents of the W register  
with register 'f'. If 'd' is 0, the result  
is stored in the W register. If 'd' is  
1, the result is stored back in  
register 'f'.  
ANDLW  
AND Literal with W  
BTFSS  
Bit Test f, Skip if Set  
Syntax:  
[label] ANDLW  
0 k 255  
k
Syntax:  
[label] BTFSS f,b  
Operands:  
Operation:  
Status Affected:  
Description:  
Operands:  
0 f 127  
0 b < 7  
(W) .AND. (k) (W)  
Operation:  
skip if (f<b>) = 1  
Z
Status Affected: None  
The contents of W register are  
AND’ed with the eight-bit literal  
'k'. The result is placed in the W  
register.  
Description: If bit 'b' in register 'f' is '0', the next  
instruction is executed.  
If bit 'b' is '1', then the next instruc-  
tion is discarded and a NOPis exe-  
cuted instead, making this a 2TCY  
instruction.  
ANDWF  
AND W with f  
Syntax:  
[label] ANDWF f,d  
Operands:  
0 f 127  
d   
Operation:  
(W) .AND. (f) (destination)  
Status Affected:  
Description:  
Z
AND the W register with register  
'f'. If 'd' is 0, the result is stored in  
the W register. If 'd' is 1, the result  
is stored back in register 'f'.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 37  
PIC16F84A  
BTFSC  
Bit Test, Skip if Clear  
CLRWDT  
Clear Watchdog Timer  
Syntax:  
[label] BTFSC f,b  
Syntax:  
[ label ] CLRWDT  
Operands:  
0 f 127  
0 b 7  
Operands:  
Operation:  
None  
00h WDT  
0 WDT prescaler,  
1 TO  
Operation:  
skip if (f<b>) = 0  
Status Affected: None  
1 PD  
Description:  
If bit 'b' in register 'f' is '1', the next  
instruction is executed.  
Status Affected: TO, PD  
If bit 'b' in register 'f' is '0', the next  
instruction is discarded, and a NOP  
is executed instead, making this a  
2TCY instruction.  
Description:  
CLRWDTinstruction resets the  
Watchdog Timer. It also resets the  
prescaler of the WDT. Status bits  
TO and PD are set.  
CALL  
Call Subroutine  
COMF  
Complement f  
Syntax:  
[ label ] CALL k  
0 k 2047  
Syntax:  
[ label ] COMF f,d  
Operands:  
Operation:  
Operands:  
0 f 127  
d [0,1]  
(PC)+ 1TOS,  
k PC<10:0>,  
(PCLATH<4:3>) PC<12:11>  
Operation:  
(f) (destination)  
Status Affected:  
Description:  
Z
Status Affected: None  
The contents of register 'f' are  
complemented. If 'd' is 0, the  
result is stored in W. If 'd' is 1, the  
result is stored back in register 'f'.  
Description:  
Call Subroutine. First, return  
address (PC+1) is pushed onto  
the stack. The eleven-bit immedi-  
ate address is loaded into PC bits  
<10:0>. The upper bits of the PC  
are loaded from PCLATH. CALLis  
a two-cycle instruction.  
DECF  
Decrement f  
CLRF  
Clear f  
Syntax:  
[label] DECF f,d  
Syntax:  
[label] CLRF  
0 f 127  
f
Operands:  
0 f 127  
d [0,1]  
Operands:  
Operation:  
00h (f)  
1 Z  
Operation:  
(f) - 1 (destination)  
Status Affected:  
Description:  
Z
Status Affected:  
Description:  
Z
Decrement register 'f'. If 'd' is 0,  
the result is stored in the W regis-  
ter. If 'd' is 1, the result is stored  
back in register 'f'.  
The contents of register 'f' are  
cleared and the Z bit is set.  
CLRW  
Clear W  
Syntax:  
[ label ] CLRW  
Operands:  
Operation:  
None  
00h (W)  
1 Z  
Status Affected:  
Description:  
Z
W register is cleared. Zero bit (Z)  
is set.  
DS35007C-page 38  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
DECFSZ  
Decrement f, Skip if 0  
INCFSZ  
Increment f, Skip if 0  
Syntax:  
[ label ] DECFSZ f,d  
Syntax:  
[ label ] INCFSZ f,d  
Operands:  
0 f 127  
d [0,1]  
Operands:  
0 f 127  
d [0,1]  
Operation:  
(f) - 1 (destination);  
Operation:  
(f) + 1 (destination),  
skip if result = 0  
skip if result = 0  
Status Affected: None  
Status Affected: None  
Description:  
The contents of register 'f' are  
Description:  
The contents of register 'f' are  
decremented. If 'd' is 0, the result  
is placed in the W register. If 'd' is  
1, the result is placed back in  
register 'f'.  
incremented. If 'd' is 0, the result is  
placed in the W register. If 'd' is 1,  
the result is placed back in  
register 'f'.  
If the result is 1, the next instruc-  
tion is executed. If the result is 0,  
then a NOPis executed instead,  
making it a 2TCY instruction.  
If the result is 1, the next instruc-  
tion is executed. If the result is 0,  
a NOPis executed instead, making  
it a 2TCY instruction.  
GOTO  
Unconditional Branch  
IORLW  
Inclusive OR Literal with W  
Syntax:  
[ label ] GOTO k  
0 k 2047  
Syntax:  
[ label ] IORLW k  
0 k 255  
Operands:  
Operation:  
Operands:  
Operation:  
Status Affected:  
Description:  
k PC<10:0>  
PCLATH<4:3> PC<12:11>  
(W) .OR. k (W)  
Z
Status Affected: None  
The contents of the W register are  
OR’ed with the eight-bit literal 'k'.  
The result is placed in the W  
register.  
Description:  
GOTOis an unconditional branch.  
The eleven-bit immediate value is  
loaded into PC bits <10:0>. The  
upper bits of PC are loaded from  
PCLATH<4:3>. GOTOis a two-  
cycle instruction.  
IORWF  
Inclusive OR W with f  
INCF  
Increment f  
Syntax:  
[ label ] IORWF f,d  
Syntax:  
[ label ] INCF f,d  
Operands:  
0 f 127  
d [0,1]  
Operands:  
0 f 127  
d [0,1]  
Operation:  
(W) .OR. (f) (destination)  
Operation:  
(f) + 1 (destination)  
Status Affected:  
Description:  
Z
Status Affected:  
Description:  
Z
Inclusive OR the W register with  
register 'f'. If 'd' is 0, the result is  
placed in the W register. If 'd' is 1,  
the result is placed back in  
register 'f'.  
The contents of register 'f' are  
incremented. If 'd' is 0, the result  
is placed in the W register. If 'd' is  
1, the result is placed back in  
register 'f'.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 39  
PIC16F84A  
MOVF  
Move f  
RETFIE  
Return from Interrupt  
Syntax:  
[ label ] MOVF f,d  
Syntax:  
[ label ] RETFIE  
Operands:  
0 f 127  
d [0,1]  
Operands:  
Operation:  
None  
TOS PC,  
1 GIE  
Operation:  
(f) (destination)  
Status Affected:  
Description:  
Z
Status Affected: None  
The contents of register f are  
moved to a destination dependant  
upon the status of d. If d = 0, des-  
tination is W register. If d = 1, the  
destination is file register f itself.  
d = 1 is useful to test a file register,  
since status flag Z is affected.  
RETLW  
Return with Literal in W  
MOVLW  
Move Literal to W  
Syntax:  
[ label ] RETLW k  
0 k 255  
Syntax:  
[ label ] MOVLW k  
0 k 255  
k (W)  
Operands:  
Operation:  
Operands:  
Operation:  
Status Affected:  
Description:  
k (W);  
TOS PC  
None  
Status Affected: None  
The eight-bit literal 'k' is loaded  
into W register. The don’t cares  
will assemble as 0’s.  
Description:  
The W register is loaded with the  
eight-bit literal 'k'. The program  
counter is loaded from the top of  
the stack (the return address).  
This is a two-cycle instruction.  
RETURN  
Return from Subroutine  
MOVWF  
Move W to f  
Syntax:  
[ label ] RETURN  
None  
Syntax:  
[ label ] MOVWF  
0 f 127  
(W) (f)  
f
Operands:  
Operation:  
Operands:  
Operation:  
Status Affected:  
Description:  
TOS PC  
Status Affected: None  
None  
Description: Return from subroutine. The stack  
Move data from W register to  
register 'f'.  
is POPed and the top of the stack  
(TOS) is loaded into the program  
counter. This is a two-cycle  
instruction.  
NOP  
No Operation  
Syntax:  
[ label ] NOP  
None  
Operands:  
Operation:  
No operation  
Status Affected: None  
Description:  
No operation.  
DS35007C-page 40  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
RLF  
Rotate Left f through Carry  
SUBLW  
Subtract W from Literal  
Syntax:  
[ label ] RLF f,d  
Syntax:  
[ label ] SUBLW k  
0 k 255  
Operands:  
0 f 127  
d [0,1]  
Operands:  
Operation:  
k - (W) W)  
Operation:  
See description below  
C
Status Affected: C, DC, Z  
Status Affected:  
Description:  
Description:  
The W register is subtracted (2’s  
The contents of register 'f' are  
rotated one bit to the left through  
the Carry Flag. If 'd' is 0, the  
result is placed in the W register.  
If 'd' is 1, the result is stored back  
in register 'f'.  
complement method) from the  
eight-bit literal 'k'. The result is  
placed in the W register.  
C
Register f  
RRF  
Rotate Right f through Carry  
SUBWF  
Subtract W from f  
Syntax:  
[ label ] RRF f,d  
Syntax:  
[ label ] SUBWF f,d  
Operands:  
0 f 127  
d [0,1]  
Operands:  
0 f 127  
d [0,1]  
Operation:  
See description below  
C
Operation:  
(f) - (W) destination)  
Status Affected:  
Description:  
Status Affected: C, DC, Z  
The contents of register 'f' are  
rotated one bit to the right through  
the Carry Flag. If 'd' is 0, the result  
is placed in the W register. If 'd' is  
1, the result is placed back in  
register 'f'.  
Description:  
Subtract (2’s complement method)  
W register from register 'f'. If 'd' is 0,  
the result is stored in the W regis-  
ter. If 'd' is 1, the result is stored  
back in register 'f'.  
C
Register f  
SWAPF  
Swap Nibbles in f  
SLEEP  
Syntax:  
[ label ] SWAPF f,d  
Syntax:  
[ label ] SLEEP  
None  
Operands:  
0 f 127  
d [0,1]  
Operands:  
Operation:  
00h WDT,  
0 WDT prescaler,  
1 TO,  
Operation:  
(f<3:0>) (destination<7:4>),  
(f<7:4>) (destination<3:0>)  
0 PD  
Status Affected: None  
Status Affected:  
Description:  
TO, PD  
Description: The upper and lower nibbles of  
register 'f' are exchanged. If 'd' is  
0, the result is placed in W regis-  
ter. If 'd' is 1, the result is placed in  
register 'f'.  
The power-down status bit, PD is  
cleared. Time-out status bit, TO  
is set. Watchdog Timer and its  
prescaler are cleared.  
The processor is put into SLEEP  
mode with the oscillator stopped.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 41  
PIC16F84A  
XORLW  
Exclusive OR Literal with W  
XORWF  
Exclusive OR W with f  
Syntax:  
[label] XORLW k  
0 k 255  
Syntax:  
[label] XORWF f,d  
Operands:  
Operation:  
Status Affected:  
Description:  
Operands:  
0 f 127  
d [0,1]  
(W) .XOR. k W)  
Z
Operation:  
(W) .XOR. (f) destination)  
Status Affected:  
Description:  
Z
The contents of the W register  
are XOR’ed with the eight-bit lit-  
eral 'k'. The result is placed in  
the W register.  
Exclusive OR the contents of the  
W register with register 'f'. If 'd' is  
0, the result is stored in the W  
register. If 'd' is 1, the result is  
stored back in register 'f'.  
DS35007C-page 42  
2001-2013 Microchip Technology Inc.  
8.1  
MPLAB Integrated Development  
Environment Software  
8.0  
DEVELOPMENT SUPPORT  
The PIC® microcontrollers and dsPIC® digital signal  
controllers are supported with a full range of software  
and hardware development tools:  
The MPLAB IDE software brings an ease of software  
development previously unseen in the 8/16/32-bit  
microcontroller market. The MPLAB IDE is a Windows®  
operating system-based application that contains:  
• Integrated Development Environment  
- MPLAB® IDE Software  
• A single graphical interface to all debugging tools  
- Simulator  
• Compilers/Assemblers/Linkers  
- MPLAB C Compiler for Various Device  
Families  
- Programmer (sold separately)  
- HI-TECH C® for Various Device Families  
- MPASMTM Assembler  
- MPLINKTM Object Linker/  
MPLIBTM Object Librarian  
- In-Circuit Emulator (sold separately)  
- In-Circuit Debugger (sold separately)  
• A full-featured editor with color-coded context  
• A multiple project manager  
- MPLAB Assembler/Linker/Librarian for  
Various Device Families  
• Customizable data windows with direct edit of  
contents  
• Simulators  
• High-level source code debugging  
• Mouse over variable inspection  
- MPLAB SIM Software Simulator  
• Emulators  
• Drag and drop variables from source to watch  
windows  
- MPLAB REAL ICE™ In-Circuit Emulator  
• In-Circuit Debuggers  
• Extensive on-line help  
• Integration of select third party tools, such as  
IAR C Compilers  
- MPLAB ICD 3  
- PICkit™ 3 Debug Express  
• Device Programmers  
- PICkit™ 2 Programmer  
- MPLAB PM3 Device Programmer  
The MPLAB IDE allows you to:  
• Edit your source files (either C or assembly)  
• One-touch compile or assemble, and download to  
emulator and simulator tools (automatically  
updates all project information)  
• Low-Cost Demonstration/Development Boards,  
Evaluation Kits, and Starter Kits  
• Debug using:  
- Source files (C or assembly)  
- Mixed C and assembly  
- Machine code  
MPLAB IDE supports multiple debugging tools in a  
single development paradigm, from the cost-effective  
simulators, through low-cost in-circuit debuggers, to  
full-featured emulators. This eliminates the learning  
curve when upgrading to tools with increased flexibility  
and power.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 43  
8.2  
MPLAB C Compilers for Various  
Device Families  
8.5  
MPLINK Object Linker/  
MPLIB Object Librarian  
The MPLAB C Compiler code development systems  
are complete ANSI C compilers for Microchip’s PIC18,  
PIC24 and PIC32 families of microcontrollers and the  
dsPIC30 and dsPIC33 families of digital signal control-  
lers. These compilers provide powerful integration  
capabilities, superior code optimization and ease of  
use.  
The MPLINK Object Linker combines relocatable  
objects created by the MPASM Assembler and the  
MPLAB C18 C Compiler. It can link relocatable objects  
from precompiled libraries, using directives from a  
linker script.  
The MPLIB Object Librarian manages the creation and  
modification of library files of precompiled code. When  
a routine from a library is called from a source file, only  
the modules that contain that routine will be linked in  
with the application. This allows large libraries to be  
used efficiently in many different applications.  
For easy source level debugging, the compilers provide  
symbol information that is optimized to the MPLAB IDE  
debugger.  
8.3  
HI-TECH C for Various Device  
Families  
The object linker/library features include:  
• Efficient linking of single libraries instead of many  
smaller files  
The HI-TECH C Compiler code development systems  
are complete ANSI C compilers for Microchip’s PIC  
family of microcontrollers and the dsPIC family of digital  
signal controllers. These compilers provide powerful  
integration capabilities, omniscient code generation  
and ease of use.  
• Enhanced code maintainability by grouping  
related modules together  
• Flexible creation of libraries with easy module  
listing, replacement, deletion and extraction  
8.6  
MPLAB Assembler, Linker and  
Librarian for Various Device  
Families  
For easy source level debugging, the compilers provide  
symbol information that is optimized to the MPLAB IDE  
debugger.  
The compilers include a macro assembler, linker, pre-  
processor, and one-step driver, and can run on multiple  
platforms.  
MPLAB Assembler produces relocatable machine  
code from symbolic assembly language for PIC24,  
PIC32 and dsPIC devices. MPLAB C Compiler uses  
the assembler to produce its object file. The assembler  
generates relocatable object files that can then be  
archived or linked with other relocatable object files and  
archives to create an executable file. Notable features  
of the assembler include:  
8.4  
MPASM Assembler  
The MPASM Assembler is a full-featured, universal  
macro assembler for PIC10/12/16/18 MCUs.  
The MPASM Assembler generates relocatable object  
files for the MPLINK Object Linker, Intel® standard HEX  
files, MAP files to detail memory usage and symbol  
reference, absolute LST files that contain source lines  
and generated machine code and COFF files for  
debugging.  
• Support for the entire device instruction set  
• Support for fixed-point and floating-point data  
• Command line interface  
• Rich directive set  
• Flexible macro language  
The MPASM Assembler features include:  
• Integration into MPLAB IDE projects  
• MPLAB IDE compatibility  
• User-defined macros to streamline  
assembly code  
• Conditional assembly for multi-purpose  
source files  
• Directives that allow complete control over the  
assembly process  
DS35007C-page 44  
2001-2013 Microchip Technology Inc.  
8.7  
MPLAB SIM Software Simulator  
8.9  
MPLAB ICD 3 In-Circuit Debugger  
System  
The MPLAB SIM Software Simulator allows code  
development in a PC-hosted environment by simulat-  
ing the PIC MCUs and dsPIC® DSCs on an instruction  
level. On any given instruction, the data areas can be  
examined or modified and stimuli can be applied from  
a comprehensive stimulus controller. Registers can be  
logged to files for further run-time analysis. The trace  
buffer and logic analyzer display extend the power of  
the simulator to record and track program execution,  
actions on I/O, most peripherals and internal registers.  
MPLAB ICD 3 In-Circuit Debugger System is Micro-  
chip's most cost effective high-speed hardware  
debugger/programmer for Microchip Flash Digital Sig-  
nal Controller (DSC) and microcontroller (MCU)  
devices. It debugs and programs PIC® Flash microcon-  
trollers and dsPIC® DSCs with the powerful, yet easy-  
to-use graphical user interface of MPLAB Integrated  
Development Environment (IDE).  
The MPLAB ICD 3 In-Circuit Debugger probe is con-  
nected to the design engineer's PC using a high-speed  
USB 2.0 interface and is connected to the target with a  
connector compatible with the MPLAB ICD 2 or MPLAB  
REAL ICE systems (RJ-11). MPLAB ICD 3 supports all  
MPLAB ICD 2 headers.  
The MPLAB SIM Software Simulator fully supports  
symbolic debugging using the MPLAB C Compilers,  
and the MPASM and MPLAB Assemblers. The soft-  
ware simulator offers the flexibility to develop and  
debug code outside of the hardware laboratory envi-  
ronment, making it an excellent, economical software  
development tool.  
8.10 PICkit 3 In-Circuit Debugger/  
Programmer and  
8.8  
MPLAB REAL ICE In-Circuit  
Emulator System  
PICkit 3 Debug Express  
The MPLAB PICkit 3 allows debugging and program-  
ming of PIC® and dsPIC® Flash microcontrollers at a  
most affordable price point using the powerful graphical  
user interface of the MPLAB Integrated Development  
Environment (IDE). The MPLAB PICkit 3 is connected  
to the design engineer's PC using a full speed USB  
interface and can be connected to the target via an  
Microchip debug (RJ-11) connector (compatible with  
MPLAB ICD 3 and MPLAB REAL ICE). The connector  
uses two device I/O pins and the reset line to imple-  
ment in-circuit debugging and In-Circuit Serial Pro-  
gramming™.  
MPLAB REAL ICE In-Circuit Emulator System is  
Microchip’s next generation high-speed emulator for  
Microchip Flash DSC and MCU devices. It debugs and  
programs PIC® Flash MCUs and dsPIC® Flash DSCs  
with the easy-to-use, powerful graphical user interface of  
the MPLAB Integrated Development Environment (IDE),  
included with each kit.  
The emulator is connected to the design engineer’s PC  
using a high-speed USB 2.0 interface and is connected  
to the target with either a connector compatible with in-  
circuit debugger systems (RJ11) or with the new high-  
speed, noise tolerant, Low-Voltage Differential Signal  
(LVDS) interconnection (CAT5).  
The PICkit 3 Debug Express include the PICkit 3, demo  
board and microcontroller, hookup cables and CDROM  
with user’s guide, lessons, tutorial, compiler and  
MPLAB IDE software.  
The emulator is field upgradable through future firmware  
downloads in MPLAB IDE. In upcoming releases of  
MPLAB IDE, new devices will be supported, and new  
features will be added. MPLAB REAL ICE offers  
significant advantages over competitive emulators  
including low-cost, full-speed emulation, run-time  
variable watches, trace analysis, complex breakpoints, a  
ruggedized probe interface and long (up to three meters)  
interconnection cables.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 45  
8.11 PICkit 2 Development  
Programmer/Debugger and  
PICkit 2 Debug Express  
8.13 Demonstration/Development  
Boards, Evaluation Kits, and  
Starter Kits  
The PICkit™ 2 Development Programmer/Debugger is  
a low-cost development tool with an easy to use inter-  
face for programming and debugging Microchip’s Flash  
families of microcontrollers. The full featured  
Windows® programming interface supports baseline  
A wide variety of demonstration, development and  
evaluation boards for various PIC MCUs and dsPIC  
DSCs allows quick application development on fully func-  
tional systems. Most boards include prototyping areas for  
adding custom circuitry and provide application firmware  
and source code for examination and modification.  
(PIC10F,  
PIC12F5xx,  
PIC16F5xx),  
midrange  
(PIC12F6xx, PIC16F), PIC18F, PIC24, dsPIC30,  
dsPIC33, and PIC32 families of 8-bit, 16-bit, and 32-bit  
microcontrollers, and many Microchip Serial EEPROM  
products. With Microchip’s powerful MPLAB Integrated  
The boards support a variety of features, including LEDs,  
temperature sensors, switches, speakers, RS-232  
interfaces, LCD displays, potentiometers and additional  
EEPROM memory.  
Development Environment (IDE) the PICkit™  
2
enables in-circuit debugging on most PIC® microcon-  
trollers. In-Circuit-Debugging runs, halts and single  
steps the program while the PIC microcontroller is  
embedded in the application. When halted at a break-  
point, the file registers can be examined and modified.  
The demonstration and development boards can be  
used in teaching environments, for prototyping custom  
circuits and for learning about various microcontroller  
applications.  
In addition to the PICDEM™ and dsPICDEM™ demon-  
stration/development board series of circuits, Microchip  
has a line of evaluation kits and demonstration software  
The PICkit 2 Debug Express include the PICkit 2, demo  
board and microcontroller, hookup cables and CDROM  
with user’s guide, lessons, tutorial, compiler and  
MPLAB IDE software.  
®
for analog filter design, KEELOQ security ICs, CAN,  
IrDA®, PowerSmart battery management, SEEVAL®  
evaluation system, Sigma-Delta ADC, flow rate  
sensing, plus many more.  
8.12 MPLAB PM3 Device Programmer  
Also available are starter kits that contain everything  
needed to experience the specified device. This usually  
includes a single application and debug capability, all  
on one board.  
The MPLAB PM3 Device Programmer is a universal,  
CE compliant device programmer with programmable  
voltage verification at VDDMIN and VDDMAX for  
maximum reliability. It features a large LCD display  
(128 x 64) for menus and error messages and a modu-  
lar, detachable socket assembly to support various  
package types. The ICSP™ cable assembly is included  
as a standard item. In Stand-Alone mode, the MPLAB  
PM3 Device Programmer can read, verify and program  
PIC devices without a PC connection. It can also set  
code protection in this mode. The MPLAB PM3  
connects to the host PC via an RS-232 or USB cable.  
The MPLAB PM3 has high-speed communications and  
optimized algorithms for quick programming of large  
memory devices and incorporates an MMC card for file  
storage and data applications.  
Check the Microchip web page (www.microchip.com)  
for the complete list of demonstration, development  
and evaluation kits.  
DS35007C-page 46  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
9.0  
ELECTRICAL CHARACTERISTICS  
Absolute Maximum Ratings †  
Ambient temperature under bias.............................................................................................................-55C to +125C  
Storage temperature .............................................................................................................................. -65C to +150C  
Voltage on any pin with respect to VSS (except VDD, MCLR, and RA4) ......................................... -0.3V to (VDD + 0.3V)  
Voltage on VDD with respect to VSS ........................................................................................................... -0.3 to +7.5V  
Voltage on MCLR with respect to VSS(1) .......................................................................................................-0.3 to +14V  
Voltage on RA4 with respect to VSS ........................................................................................................... -0.3 to +8.5V  
Total power dissipation(2) .....................................................................................................................................800 mW  
Maximum current out of VSS pin ...........................................................................................................................150 mA  
Maximum current into VDD pin ..............................................................................................................................100 mA  
Input clamp current, IIK (VI < 0 or VI > VDD)20 mA  
Output clamp current, IOK (VO < 0 or VO > VDD) 20 mA  
Maximum output current sunk by any I/O pin..........................................................................................................25 mA  
Maximum output current sourced by any I/O pin ....................................................................................................25 mA  
Maximum current sunk byPORTA..........................................................................................................................80 mA  
Maximum current sourced by PORTA.....................................................................................................................50 mA  
Maximum current sunk by PORTB........................................................................................................................150 mA  
Maximum current sourced by PORTB ..................................................................................................................100 mA  
Note 1: Voltage spikes below VSS at the MCLR pin, inducing currents greater than 80 mA, may cause latch-up.  
Thus, a series resistor of 50-100should be used when applying a “low” level to the MCLR pin rather than  
pulling this pin directly to VSS.  
2: Power dissipation is calculated as follows: Pdis = VDD x {IDD - IOH} + {(VDD-VOH) x IOH} + (VOl x IOL).  
† NOTICE: Stresses above those listed under “Absolute Maximum Ratings” may cause permanent damage to the  
device. This is a stress rating only and functional operation of the device at those or any other conditions above  
those indicated in the operation listings of this specification is not implied. Exposure to maximum rating conditions for  
extended periods may affect device reliability.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 47  
PIC16F84A  
FIGURE 9-1:  
PIC16F84A-20 VOLTAGE-FREQUENCY GRAPH  
6.0V  
5.5V  
5.0V  
4.5V  
4.0V  
3.5V  
3.0V  
2.5V  
2.0V  
20 MHz  
Frequency  
FIGURE 9-2:  
PIC16LF84A-04 VOLTAGE-  
FREQUENCY GRAPH  
FIGURE 9-3:  
PIC16F84A-04 VOLTAGE-  
FREQUENCY GRAPH  
6.0V  
5.5V  
6.0V  
5.5V  
5.0V  
4.5V  
4.0V  
5.0V  
4.5V  
4.0V  
3.5V  
3.0V  
2.5V  
3.5V  
3.0V  
2.5V  
2.0V  
2.0V  
4 MHz  
10 MHz  
Frequency  
4 MHz  
FMAX = (6.0 MHz/V) (VDDAPPMIN - 2.0V) + 4 MHz  
Frequency  
Note 1: VDDAPPMIN is the minimum voltage of the  
®
PIC device in the application.  
2: FMAX has a maximum frequency of 10 MHz.  
DS35007C-page 48  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
9.1  
DC Characteristics  
Standard Operating Conditions (unless otherwise stated)  
PIC16LF84A-04  
(Commercial, Industrial)  
Operating temperature  
0C TA +70C (commercial)  
-40C TA +85C (industrial)  
-40C TA +125C (extended)  
PIC16F84A-04  
Standard Operating Conditions (unless otherwise stated)  
(Commercial, Industrial, Extended)  
PIC16F84A-20  
(Commercial, Industrial, Extended)  
Operating temperature  
0C TA +70C (commercial)  
-40C TA +85C (industrial)  
-40C TA +125C (extended)  
Param  
No.  
Symbol  
Characteristic  
Min Typ† Max Units  
Conditions  
VDD  
Supply Voltage  
D001  
16LF84A 2.0  
5.5  
V
XT, RC, and LP osc configuration  
D001  
D001A  
16F84A 4.0  
4.5  
5.5  
5.5  
V
V
XT, RC and LP osc configuration  
HS osc configuration  
D002 VDR  
RAM Data Retention  
Voltage (Note 1)  
1.5  
V
Device in SLEEP mode  
D003 VPOR  
VDD Start Voltage to ensure  
internal Power-on Reset  
signal  
Vss  
V
See section on Power-on Reset for details  
D004 SVDD  
VDD Rise Rate to ensure  
internal Power-on Reset  
signal  
0.05  
4
V/ms  
IDD  
Supply Current (Note 2)  
D010  
16LF84A  
1
mA RC and XT osc configuration (Note 4)  
FOSC = 2.0 MHz, VDD = 5.5V  
D010  
16F84A  
1.8  
3
4.5  
10  
mA RC and XT osc configuration (Note 4)  
FOSC = 4.0 MHz, VDD = 5.5V  
mA RC and XT osc configuration (Note 4)  
FOSC = 4.0 MHz, VDD = 5.5V  
D010A  
(During FLASH programming)  
D013  
D014  
10  
15  
20  
45  
mA HS osc configuration (PIC16F84A-20)  
FOSC = 20 MHz, VDD = 5.5V  
16LF84A  
A LP osc configuration  
FOSC = 32 kHz, VDD = 2.0V, WDT disabled  
Legend: Rows with standard voltage device data only are shaded for improved readability.  
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
NR Not rated for operation.  
Note 1: This is the limit to which VDD can be lowered without losing RAM data.  
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O  
pin loading and switching rate, oscillator type, internal code execution pattern, and temperature also have  
an impact on the current consumption.  
The test conditions for all IDD measurements in active operation mode are:  
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD,  
T0CKI = VDD, MCLR = VDD; WDT enabled/disabled as specified.  
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is  
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD and VSS.  
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be  
estimated by the formula IR = VDD/2REXT (mA) with REXT in kOhm.  
5: The current is the additional current consumed when this peripheral is enabled. This current should be  
added to the base IDD measurement.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 49  
PIC16F84A  
9.1  
DC Characteristics (Continued)  
Standard Operating Conditions (unless otherwise stated)  
PIC16LF84A-04  
(Commercial, Industrial)  
Operating temperature  
0C TA +70C (commercial)  
-40C TA +85C (industrial)  
-40C TA +125C (extended)  
PIC16F84A-04  
Standard Operating Conditions (unless otherwise stated)  
(Commercial, Industrial, Extended)  
PIC16F84A-20  
(Commercial, Industrial, Extended)  
Operating temperature  
0C TA +70C (commercial)  
-40C TA +85C (industrial)  
-40C TA +125C (extended)  
Param  
No.  
Symbol  
Characteristic  
Min Typ† Max Units  
Conditions  
IPD  
Power-down Current (Note 3)  
D020  
D020  
16LF84A  
16F84A-20  
16F84A-04  
D021A  
D021A  
16LF84A  
0.4  
1.0  
A VDD = 2.0V, WDT disabled, industrial  
16F84A-20  
16F84A-04  
1.5  
1.0  
3.5  
3.0  
A VDD = 4.5V, WDT disabled, industrial  
A VDD = 4.0V, WDT disabled, industrial  
D021B  
16F84A-20  
16F84A-04  
1.5  
1.0  
5.5  
5.0  
A VDD = 4.5V, WDT disabled, extended  
A VDD = 4.0V, WDT disabled, extended  
Module Differential Current  
(Note 5)  
D022 IWDT  
Watchdog Timer  
.20  
3.5  
3.5  
4.8  
4.8  
16  
20  
28  
25  
30  
A VDD = 2.0V, Industrial, Commercial  
A VDD = 4.0V, Commercial  
A VDD = 4.0V, Industrial, Extended  
A VDD = 4.5V, Commercial  
A VDD = 4.5V, Industrial, Extended  
Legend: Rows with standard voltage device data only are shaded for improved readability.  
Data in "Typ" column is at 5.0V, 25°C unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
NR Not rated for operation.  
Note 1: This is the limit to which VDD can be lowered without losing RAM data.  
2: The supply current is mainly a function of the operating voltage and frequency. Other factors, such as I/O  
pin loading and switching rate, oscillator type, internal code execution pattern, and temperature also have  
an impact on the current consumption.  
The test conditions for all IDD measurements in active operation mode are:  
OSC1 = external square wave, from rail-to-rail; all I/O pins tri-stated, pulled to VDD,  
T0CKI = VDD, MCLR = VDD; WDT enabled/disabled as specified.  
3: The power-down current in SLEEP mode does not depend on the oscillator type. Power-down current is  
measured with the part in SLEEP mode, with all I/O pins in hi-impedance state and tied to VDD and VSS.  
4: For RC osc configuration, current through REXT is not included. The current through the resistor can be  
estimated by the formula IR = VDD/2REXT (mA) with REXT in kOhm.  
5: The current is the additional current consumed when this peripheral is enabled. This current should be  
added to the base IDD measurement.  
DS35007C-page 50  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
9.2  
DC Characteristics:  
PIC16F84A-04 (Commercial, Industrial)  
PIC16F84A-20 (Commercial, Industrial)  
PIC16LF84A-04 (Commercial, Industrial)  
Standard Operating Conditions (unless otherwise stated)  
Operating temperature  
0C  
TA +70C (commercial)  
DC Characteristics  
All Pins Except Power Supply Pins  
-40C TA +85C (industrial)  
Operating voltage VDD range as described in DC specifications  
(Section 9.1)  
Param  
No.  
Symbol  
Characteristic  
Min  
Typ†  
Max  
Units  
Conditions  
VIL  
Input Low Voltage  
I/O ports:  
D030  
D030A  
D031  
D032  
D033  
D034  
with TTL buffer  
VSS  
VSS  
VSS  
VSS  
VSS  
VSS  
0.8  
V
V
V
V
V
V
4.5V VDD 5.5V (Note 4)  
Entire range (Note 4)  
Entire range  
0.16VDD  
0.2VDD  
0.2VDD  
0.3VDD  
0.1VDD  
with Schmitt Trigger buffer  
MCLR, RA4/T0CKI  
OSC1 (XT, HS and LP modes)  
OSC1 (RC mode)  
(Note 1)  
VIH  
Input High Voltage  
I/O ports:  
D040  
D040A  
with TTL buffer  
2.0  
0.25VDD+0.8  
VDD  
VDD  
V
V
4.5V VDD 5.5V (Note 4)  
Entire range (Note 4)  
D041  
with Schmitt Trigger buffer  
MCLR,  
0.8 VDD  
0.8 VDD  
0.8 VDD  
0.8 VDD  
0.9 VDD  
VDD  
VDD  
8.5  
Entire range  
D042  
V
V
V
V
V
D042A  
D043  
RA4/T0CKI  
OSC1 (XT, HS and LP modes)  
OSC1 (RC mode)  
VDD  
VDD  
(Note 1)  
D043A  
D050 VHYS  
Hysteresis of Schmitt Trigger  
Inputs  
0.1  
D070 IPURB  
IIL  
PORTB Weak Pull-up Current  
50  
250  
400  
A VDD = 5.0V, VPIN = VSS  
Input Leakage Current  
(Notes 2, 3)  
D060  
I/O ports  
1  
A Vss VPIN VDD,  
Pin at hi-impedance  
D061  
D063  
MCLR, RA4/T0CKI  
OSC1  
5  
5  
A Vss VPIN VDD  
A Vss VPIN VDD, XT, HS  
and LP osc configuration  
Data in “Typ” column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. Do not drive the PIC16F84A with an  
external clock while the device is in RC mode, or chip damage may result.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified  
levels represent normal operating conditions. Higher leakage current may be measured at different input  
voltages.  
3: Negative current is defined as coming out of the pin.  
4: The user may choose the better of the two specs.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 51  
PIC16F84A  
9.2  
DC Characteristics:  
PIC16F84A-04 (Commercial, Industrial)  
PIC16F84A-20 (Commercial, Industrial)  
PIC16LF84A-04 (Commercial, Industrial) (Continued)  
Standard Operating Conditions (unless otherwise stated)  
Operating temperature  
0C  
TA +70C (commercial)  
DC Characteristics  
All Pins Except Power Supply Pins  
-40C TA +85C (industrial)  
Operating voltage VDD range as described in DC specifications  
(Section 9.1)  
Param  
No.  
Symbol  
Characteristic  
Min  
Typ†  
Max  
Units  
Conditions  
VOL  
Output Low Voltage  
I/O ports  
D080  
D083  
0.6  
0.6  
V
V
IOL = 8.5 mA, VDD = 4.5V  
OSC2/CLKOUT  
IOL = 1.6 mA, VDD = 4.5V,  
(RC mode only)  
VOH  
VOD  
Output High Voltage  
I/O ports (Note 3)  
D090  
D092  
VDD-0.7  
VDD-0.7  
V
V
IOH = -3.0 mA, VDD = 4.5V  
OSC2/CLKOUT (Note 3)  
IOH = -1.3 mA, VDD = 4.5V  
(RC mode only)  
Open Drain High Voltage  
D150  
RA4 pin  
8.5  
V
Capacitive Loading Specs on  
Output Pins  
D100 COSC2 OSC2 pin  
15  
50  
pF In XT, HS and LP modes  
when external clock is used  
to drive OSC1  
D101 CIO  
All I/O pins and OSC2  
pF  
(RC mode)  
Data EEPROM Memory  
Endurance  
D120 ED  
1M  
10M  
E/W 25C at 5V  
D121 VDRW  
VDD for read/write  
VMIN  
5.5  
V
VMIN = Minimum operating  
voltage  
D122 TDEW  
Erase/Write cycle time  
Program FLASH Memory  
Endurance  
4
8
ms  
D130 EP  
1000  
VMIN  
10K  
E/W  
V
D131 VPR  
VDD for read  
5.5  
VMIN = Minimum operating  
voltage  
D132 VPEW  
D133 TPEW  
VDD for erase/write  
4.5  
4
5.5  
8
V
Erase/Write cycle time  
ms  
Data in “Typ” column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
Note 1: In RC oscillator configuration, the OSC1 pin is a Schmitt Trigger input. Do not drive the PIC16F84A with an  
external clock while the device is in RC mode, or chip damage may result.  
2: The leakage current on the MCLR pin is strongly dependent on the applied voltage level. The specified  
levels represent normal operating conditions. Higher leakage current may be measured at different input  
voltages.  
3: Negative current is defined as coming out of the pin.  
4: The user may choose the better of the two specs.  
DS35007C-page 52  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
9.3  
AC (Timing) Characteristics  
9.3.1  
TIMING PARAMETER SYMBOLOGY  
The timing parameter symbols have been created fol-  
lowing one of the following formats:  
1. TppS2ppS  
2. TppS  
T
F
Frequency  
T
Time  
Lowercase letters (pp) and their meanings:  
pp  
2
to  
os, osc  
ost  
OSC1  
ck  
cy  
io  
CLKOUT  
cycle time  
I/O port  
INT pin  
MCLR  
oscillator start-up timer  
power-up timer  
RBx pins  
pwrt  
rbt  
inp  
mp  
t0  
T0CKI  
wdt  
watchdog timer  
Uppercase letters and their meanings:  
S
F
H
I
Fall  
P
R
V
Z
Period  
High  
Rise  
Invalid (high impedance)  
Low  
Valid  
L
High Impedance  
2001-2013 Microchip Technology Inc.  
DS35007C-page 53  
PIC16F84A  
9.3.2  
TIMING CONDITIONS  
The temperature and voltages specified in Table 9-1  
apply to all timing specifications unless otherwise  
noted. All timings are measured between high and low  
measurement points as indicated in Figure 9-4.  
Figure 9-5 specifies the load conditions for the timing  
specifications.  
TABLE 9-1:  
TEMPERATURE AND VOLTAGE SPECIFICATIONS - AC  
Standard Operating Conditions (unless otherwise stated)  
Operating temperature  
0°C TA +70°C for commercial  
-40°C TA +85°C for industrial  
AC CHARACTERISTICS  
Operating voltage VDD range as described in DC specifications (Section 9.1)  
FIGURE 9-4:  
PARAMETER MEASUREMENT INFORMATION  
0.7 VDD XTAL  
0.8 VDD RC  
(High)  
0.9 VDD (High)  
0.1 VDD (Low)  
0.3 VDD XTAL  
0.15 VDD RC  
(Low)  
OSC1 Measurement Points  
I/O Port Measurement Points  
FIGURE 9-5:  
LOAD CONDITIONS  
Load Condition 1  
VDD/2  
Load Condition 2  
CL  
RL  
Pin  
VSS  
CL  
Pin  
VSS  
RL =  
CL =  
464  
50 pF  
15 pF  
for all pins except OSC2  
for OSC2 output  
DS35007C-page 54  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
9.3.3  
TIMING DIAGRAMS AND SPECIFICATIONS  
EXTERNAL CLOCK TIMING  
FIGURE 9-6:  
Q4  
Q3  
Q4  
Q1  
Q1  
Q2  
OSC1  
1
3
3
4
4
2
CLKOUT  
TABLE 9-2:  
EXTERNAL CLOCK TIMING REQUIREMENTS  
Param No. Sym  
Characteristic  
Min  
Typ†  
Max  
Units  
Conditions  
FOSC External CLKIN Frequency(1)  
DC  
DC  
DC  
DC  
DC  
DC  
0.1  
0.1  
1.0  
DC  
500  
250  
50  
2
4
MHz XT, RC osc  
MHz XT, RC osc  
MHz HS osc  
kHz LP osc  
MHz RC osc  
MHz RC osc  
MHz XT osc  
MHz XT osc  
MHz HS osc  
kHz LP osc  
ns XT, RC osc  
ns XT, RC osc  
ns HS osc  
s LP osc  
ns RC osc  
ns RC osc  
ns XT osc  
ns XT osc  
ns HS osc  
s LP osc  
s  
(-04, LF)  
(-04)  
20  
200  
2
(-20)  
(-04, LF)  
(-04, LF)  
(-04)  
Oscillator Frequency(1)  
4
2
(-04, LF)  
(-04)  
4
20  
200  
(-20)  
(-04, LF)  
(-04, LF)  
(-04)  
1
TOSC  
External CLKIN Period(1)  
Oscillator Period(1)  
(-20)  
5.0  
500  
250  
500  
250  
50  
(-04, LF)  
(-04, LF)  
(-04)  
10,000  
10,000  
1,000  
(-04, LF)  
(-04)  
(-20)  
5.0  
0.2  
60  
(-04, LF)  
2
3
TCY  
Instruction Cycle Time(1)  
4/FOSC  
DC  
TosL, Clock in (OSC1) High or Low  
TosH Time  
ns XT osc  
ns XT osc  
s LP osc  
ns HS osc  
ns XT osc  
ns LP osc  
ns HS osc  
(-04, LF)  
(-04)  
50  
2.0  
17.5  
25  
(-04, LF)  
(-20)  
4
TosR, Clock in (OSC1) Rise or Fall  
(-04)  
TosF  
Time  
50  
(-04, LF)  
(-20)  
7.5  
Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
Note 1: Instruction cycle period (TCY) equals four times the input oscillator time-base period. All specified values  
are based on characterization data for that particular oscillator type under standard operating conditions  
with the device executing code. Exceeding these specified limits may result in an unstable oscillator opera-  
tion and/or higher than expected current consumption. All devices are tested to operate at "Min." values  
with an external clock applied to the OSC1 pin.  
When an external clock input is used, the "Max." cycle time limit is "DC" (no clock) for all devices.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 55  
PIC16F84A  
FIGURE 9-7:  
CLKOUT AND I/O TIMING  
Q1  
Q2  
Q3  
Q4  
OSC1  
11  
10  
22  
23  
CLKOUT  
13  
12  
19  
18  
14  
16  
I/O Pin  
(Input)  
15  
17  
I/O Pin  
(Output)  
new value  
old value  
20, 21  
Note:  
All tests must be done with specified capacitive loads (Figure 9-5) 50 pF on I/O pins and CLKOUT.  
TABLE 9-3:  
CLKOUT AND I/O TIMING REQUIREMENTS  
Param  
No.  
Sym  
Characteristic  
Min  
Typ†  
Max  
Units Conditions  
10  
TosH2ckL OSC1to CLKOUT  
Standard  
15  
15  
15  
15  
15  
15  
15  
15  
10  
10  
10  
10  
30  
120  
30  
ns (Note 1)  
10A  
11  
Extended (LF)  
Standard  
ns (Note 1)  
TosH2ckH OSC1to CLKOUT  
ns (Note 1)  
11A  
12  
Extended (LF)  
Standard  
120  
30  
ns (Note 1)  
TckR  
TckF  
CLKOUT rise time  
CLKOUT fall time  
ns (Note 1)  
12A  
13  
Extended (LF)  
Standard  
100  
30  
ns (Note 1)  
ns (Note 1)  
13A  
14  
Extended (LF)  
100  
0.5TCY +20  
ns (Note 1)  
TckL2ioV CLKOUT to Port out valid  
ns (Note 1)  
15  
TioV2ckH Port in valid before  
Standard  
0.30TCY + 30  
ns (Note 1)  
CLKOUT   
Extended (LF)  
0.30TCY + 80  
ns (Note 1)  
16  
17  
TckH2ioI Port in hold after CLKOUT   
0
ns (Note 1)  
TosH2ioV OSC1(Q1 cycle) to  
Standard  
125  
250  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
Port out valid  
Extended (LF)  
Standard  
18  
19  
TosH2ioI OSC1(Q2 cycle) to Port  
10  
input invalid (I/O in hold time)  
Extended (LF)  
Standard  
10  
TioV2osH Port input valid to OSC1  
-75  
-175  
(I/O in setup time)  
Extended (LF)  
Standard  
20  
TioR  
TioF  
TINP  
TRBP  
Port output rise time  
Port output fall time  
35  
20A  
21  
Extended (LF)  
Standard  
70  
35  
21A  
22  
Extended (LF)  
Standard  
70  
INT pin high  
or low time  
20  
22A  
23  
Extended (LF)  
Standard  
55  
RB7:RB4 change INT  
high or low time  
TOSC§  
TOSC§  
23A  
Extended (LF)  
§
Data in "Typ" column is at 5.0V, 25C unless otherwise stated. These parameters are for design guidance only and are not tested.  
By design.  
Note 1: Measurements are taken in RC mode where CLKOUT output is 4 x TOSC.  
DS35007C-page 56  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 9-8:  
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND POWER-UP  
TIMER TIMING  
VDD  
MCLR  
30  
Internal  
POR  
33  
PWRT  
Time-out  
32  
OSC  
Time-out  
Internal  
Reset  
Watchdog  
Timer  
Reset  
31  
34  
34  
I/O Pins  
TABLE 9-4:  
RESET, WATCHDOG TIMER, OSCILLATOR START-UP TIMER AND  
POWER-UP TIMER REQUIREMENTS  
Parameter  
No.  
Sym  
Characteristic  
Min  
Typ†  
Max Units  
Conditions  
s VDD = 5.0V  
ms VDD = 5.0V  
30  
31  
TmcL  
TWDT  
MCLR Pulse Width (low)  
2
7
Watchdog Timer Time-out  
Period (No Prescaler)  
18  
33  
Oscillation Start-up Timer  
Period  
32  
33  
TOST  
1024TOSC  
72  
ms TOSC = OSC1 period  
ms VDD = 5.0V  
TPWRT Power-up Timer Period  
28  
132  
100  
I/O hi-impedance from MCLR  
Low or RESET  
34  
TIOZ  
ns  
† Data in "Typ" column is at 5V, 25C, unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 57  
PIC16F84A  
FIGURE 9-9:  
TIMER0 CLOCK TIMINGS  
RA4/T0CKI  
40  
41  
42  
TABLE 9-5:  
TIMER0 CLOCK REQUIREMENTS  
Parameter  
No.  
Sym  
Characteristic  
Min  
Typ† Max Units  
Conditions  
40  
41  
42  
Tt0H T0CKI High Pulse  
No Prescaler  
0.5TCY + 20  
ns  
Width  
With Prescaler  
50  
30  
ns 2.0V VDD 3.0V  
ns 3.0V VDD 6.0V  
Tt0L T0CKI Low Pulse  
Width  
No Prescaler  
0.5TCY + 20  
ns  
With Prescaler  
50  
20  
ns 2.0V VDD 3.0V  
ns 3.0V VDD 6.0V  
Tt0P T0CKI Period  
TCY + 40  
N
ns N = prescale value  
(2, 4, ..., 256)  
† Data in "Typ" column is at 5.0V, 25C, unless otherwise stated. These parameters are for design guidance  
only and are not tested.  
DS35007C-page 58  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
10.0 DC/AC CHARACTERISTIC GRAPHS  
The graphs provided in this section are for design guidance and are not tested.  
In some graphs, the data presented are outside specified operating range (i.e., outside specified VDD range). This is  
for information only and devices are ensured to operate properly only within the specified range.  
The data presented in this section is a statistical summary of data collected on units from different lots over a period  
of time and matrix samples. ‘Typical’ represents the mean of the distribution at 25C. ‘Max’ or ‘Min’ represents  
(mean + 3) or (mean - 3), respectively, where is a standard deviation over the whole temperature range.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 59  
PIC16F84A  
FIGURE 10-1:  
TYPICAL IDD vs. FOSC OVER VDD (HS MODE, 25°C)  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
5.5 V  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0.0  
4
6
8
10  
12  
14  
16  
18  
20  
FOSC (MHz)  
FIGURE 10-2:  
MAXIMUM IDD vs. FOSC OVER VDD (HS MODE, -40° TO +125°C)  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
1.0  
0.5  
5.5 V  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0.0  
4
6
8
10  
12  
14  
16  
18  
20  
FOSC (MHz)  
DS35007C-page 60  
© 2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 10-3:  
TYPICAL IDD vs. FOSC OVER VDD (XT MODE, 25°C)  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
5.5 V  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0.0  
0.0  
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
FOSC (MHz)  
FIGURE 10-4:  
MAXIMUM IDD vs. FOSC OVER VDD (XT MODE, -40° TO +125°C)  
1.0  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
5.5 V  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0.0  
0.0  
0.5  
1.0  
1.5  
2.0  
2.5  
3.0  
3.5  
4.0  
FOSC (MHz)  
2001-2013 Microchip Technology Inc.  
DS35007C-page 61  
PIC16F84A  
FIGURE 10-5:  
TYPICAL IDD vs. FOSC OVER VDD (LP MODE, 25°C)  
80  
70  
60  
50  
40  
30  
20  
10  
5.5 V  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0
25  
50  
75  
100  
125  
150  
175  
200  
FOSC (kHz)  
FIGURE 10-6:  
MAXIMUM IDD vs. FOSC OVER VDD (LP MODE, -40° TO +125°C)  
250  
5.5 V  
200  
150  
100  
50  
5.0 V  
4.5 V  
4.0 V  
3.5 V  
3.0 V  
2.5 V  
2.0 V  
0
25  
50  
75  
100  
125  
150  
175  
200  
FOSC (kHz)  
DS35007C-page 62  
© 2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 10-7:  
AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 22 pF, 25C)  
16.0  
14.0  
12.0  
10.0  
8.0  
3.3 k  
5.1 k  
10 k  
6.0  
4.0  
2.0  
100 k  
0.0  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
FIGURE 10-8:  
AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 100 pF, 25C)  
2000  
1800  
1600  
1400  
1200  
1000  
800  
3.3 k  
5.1 k  
10 k  
600  
400  
200  
100 k  
0
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
2001-2013 Microchip Technology Inc.  
DS35007C-page 63  
PIC16F84A  
FIGURE 10-9:  
AVERAGE FOSC vs. VDD FOR R (RC MODE, C = 300 pF, 25C)  
900  
800  
700  
600  
500  
400  
300  
200  
100  
3.3 k  
5.1 k  
10 k  
100 k  
0
VDD (V)  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
FIGURE 10-10:  
IPD vs. VDD (SLEEP MODE, ALL PERIPHERALS DISABLED)  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
10.0  
Max  
1.0  
Typ  
0.1  
0.0  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
DS35007C-page 64  
© 2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 10-11:  
IPD vs. VDD (WDT MODE)  
15  
Typical:  
statistical mean @ 25°C  
14  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
13  
12  
11  
10  
9
Max  
8
7
6
5
Typ  
4
3
2
1
0
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
FIGURE 10-12:  
TYPICAL, MINIMUM, AND MAXIMUM WDT PERIOD vs. VDD OVER TEMP  
60  
50  
40  
30  
20  
Max  
Typ  
Min  
10  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
0
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
2001-2013 Microchip Technology Inc.  
DS35007C-page 65  
PIC16F84A  
FIGURE 10-13:  
TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 5V, -40C TO +125C)  
5.0  
4.5  
4.0  
3.5  
3.0  
2.5  
2.0  
1.5  
Ma  
Typ  
Min  
1.0  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
0.5  
0.0  
0.0  
2.5  
5.0  
7.5  
10.0  
12.5  
15.0  
17.5  
20.0  
22.5  
25.0  
IOH (mA)  
FIGURE 10-14:  
TYPICAL, MINIMUM AND MAXIMUM VOH vs. IOH (VDD = 3V, -40C TO +125C)  
3.0  
2.5  
2.0  
1.5  
1.0  
Max  
Typ  
Min  
0.5  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
0.0  
0
5
10  
15  
20  
25  
IOH (mA)  
DS35007C-page 66  
© 2001-2013 Microchip Technology Inc.  
PIC16F84A  
FIGURE 10-15:  
TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 5V, -40C TO +125C)  
1.0  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
0.9  
0.8  
0.7  
0.6  
0.5  
0.4  
0.3  
0.2  
0.1  
0.0  
Max  
Typ  
Min  
0
5
10  
15  
20  
25  
IOL (mA)  
FIGURE 10-16:  
TYPICAL, MINIMUM AND MAXIMUM VOL vs. IOL (VDD = 3V, -40C TO +125C)  
1.8  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
1.6  
1.4  
1.2  
1.0  
0.8  
0.6  
0.4  
0.2  
0.0  
Max  
Typ  
Min  
0.0  
2.5  
5.0  
7.5  
10.0  
12.5  
15.0  
17.5  
20.0  
22.5  
25.0  
IOL (mA)  
2001-2013 Microchip Technology Inc.  
DS35007C-page 67  
PIC16F84A  
FIGURE 10-17:  
MINIMUM AND MAXIMUM VIN vs. VDD, (TTL INPUT, -40C TO +125C)  
2.00  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
1.75  
1.50  
1.25  
1.00  
0.75  
0.50  
0.25  
0.00  
VTH  
VTH  
VTH  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
FIGURE 10-18:  
MINIMUM AND MAXIMUM VIN vs. VDD (ST INPUT, -40C TO +125C)  
3.50  
Typical:  
statistical mean @ 25°C  
Maximum: mean + 3(-40°C to +125°C)  
Minimum: mean – 3(-40°C to +125°C)  
3.25  
3.00  
2.75  
2.50  
2.25  
2.00  
1.75  
1.50  
1.25  
1.00  
0.75  
0.50  
VIH Typ  
VIH Max  
VIH Min  
VIL Typ  
VIL Max  
VIL Min  
2.0  
2.5  
3.0  
3.5  
4.0  
4.5  
5.0  
5.5  
VDD (V)  
DS35007C-page 68  
© 2001-2013 Microchip Technology Inc.  
PIC16F84A  
11.0 PACKAGING INFORMATION  
11.1 Package Marking Information  
18-Lead PDIP (300 mil)  
Example  
PIC16F84A-04I/P  
0110017  
e
3
18-Lead SOIC (7.50 mm)  
Example  
PIC16F84A-04  
/SO  
e
3
0110017  
20-Lead SSOP (5.30 mm)  
Example  
PIC16F84A-  
20/SS  
e
3
0110017  
Legend: XX...X Customer-specific information  
Y
YY  
Year code (last digit of calendar year)  
Year code (last 2 digits of calendar year)  
WW  
NNN  
Week code (week of January 1 is week ‘01’)  
Alphanumeric traceability code  
e
3
Pb-free JEDEC designator for Matte Tin (Sn)  
*
This package is Pb-free. The Pb-free JEDEC designator (  
can be found on the outer packaging for this package.  
)
e3  
Note: In the event the full Microchip part number cannot be marked on one line, it will  
be carried over to the next line, thus limiting the number of available  
characters for customer-specific information.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 69  
PIC16F84A  
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ꢔꢄꢌꢉꢋꢌꢍꢄꢓ ꢌꢍꢅꢋꢇꢋꢑꢊ ꢒꢉꢆ*ꢄꢅꢑ ,ꢕꢖꢞꢕꢕꢜ1  
DS35007C-page 70  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
Note: For the most current package drawings, please see the Microchip Packaging Specification located at  
http://www.microchip.com/packaging  
2001-2013 Microchip Technology Inc.  
DS35007C-page 71  
PIC16F84A  
Note: For the most current package drawings, please see the Microchip Packaging Specification located at  
http://www.microchip.com/packaging  
DS35007C-page 72  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
Note: For the most current package drawings, please see the Microchip Packaging Specification located at  
http://www.microchip.com/packaging  
2001-2013 Microchip Technology Inc.  
DS35007C-page 73  
PIC16F84A  
!ꢕꢂꢃꢄꢅꢆꢇꢈꢉꢅꢊꢋꢌꢍꢇ"#$ꢌꢑ%ꢇ"ꢖꢅꢉꢉꢇ&ꢏꢋꢉꢌꢑꢄꢇꢒ""ꢓꢇMꢇ'(ꢔꢕꢇꢖꢖꢇꢗꢘꢆꢙꢇꢚ""&ꢈꢛꢇ  
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ꢔꢄꢌꢉꢋꢌꢍꢄꢓ ꢌꢍꢅꢋꢇꢋꢑꢊ ꢒꢉꢆ*ꢄꢅꢑ ,ꢕꢖꢞꢕꢜꢎ1  
DS35007C-page 74  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
Note: For the most current package drawings, please see the Microchip Packaging Specification located at  
http://www.microchip.com/packaging  
2001-2013 Microchip Technology Inc.  
DS35007C-page 75  
PIC16F84A  
NOTES:  
DS35007C-page 76  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
APPENDIX A: REVISION HISTORY  
Version  
Date  
Revision Description  
A
9/1998  
This is a new data sheet. However, the devices described in this data sheet are  
the upgrades to the devices found in the PIC16F8X Data Sheet, DS30430.  
B
C
05/2001  
11/2011  
Added DC and AC Characteristics Graphs and Tables to Section 10.  
Updated the “Packaging Information” section.  
2001-2013 Microchip Technology Inc.  
DS35007C-page 77  
PIC16F84A  
APPENDIX B: CONVERSION CONSIDERATIONS  
Considerations for converting from one PIC16X8X  
device to another are listed in Table 1.  
TABLE 1:  
CONVERSION CONSIDERATIONS - PIC16C84, PIC16F83/F84, PIC16CR83/CR84,  
PIC16F84A  
PIC16CR83/  
CR84  
Difference  
PIC16C84  
PIC16F83/F84  
PIC16F84A  
Program Memory Size  
Data Memory Size  
Voltage Range  
1K x 14  
36 x 8  
512 x 14 / 1K x 14  
36 x 8 / 68 x 8  
512 x 14 / 1K x 14  
36 x 8 / 68 x 8  
1K x 14  
68 x 8  
2.0V - 6.0V  
2.0V - 6.0V  
2.0V - 6.0V  
2.0V - 5.5V  
(-40C to +85C)  
(-40C to +85C)  
(-40C to +85C)  
(-40C to +125C)  
Maximum Operating Fre- 10 MHz  
quency  
10 MHz  
10 MHz  
20 MHz  
Supply Current (IDD).  
See parameter # D014 in IDD (max) = 400 A  
IDD (typ) = 60 A  
IDD (typ) = 15 A  
IDD (max) = 45 A  
IDD (typ) = 15 A  
IDD (max) = 45 A  
IDD (typ) = 15 A  
IDD (max) = 45 A  
the electrical specs for  
(LP osc, FOSC = 32 kHz, (LP osc, FOSC = 32 kHz, (LP osc, FOSC = 32 kHz, (LP osc, FOSC = 32 kHz,  
more detail.  
VDD = 2.0V,  
VDD = 2.0V,  
VDD = 2.0V,  
VDD = 2.0V,  
WDT disabled)  
WDT disabled)  
WDT disabled)  
WDT disabled)  
Power-down Current  
(IPD). See parameters # IPD (max) = 100 A  
D020, D021, and D021A (VDD = 2.0V,  
IPD (typ) = 26 A  
IPD (typ) = 0.4 A  
IPD (max) = 9 A  
(VDD = 2.0V,  
IPD (typ) = 0.4 A  
IPD (max) = 6 A  
(VDD = 2.0V,  
IPD (typ) = 0.4 A  
IPD (max) = 1 A  
(VDD = 2.0V,  
in the electrical specs for WDT disabled, industrial) WDT disabled, industrial) WDT disabled, industrial) WDT disabled, industrial)  
more detail.  
Input Low Voltage (VIL). VIL (max) = 0.2VDD  
See parameters # D032 (OSC1, RC mode)  
and D034 in the electrical  
VIL (max) = 0.1VDD  
(OSC1, RC mode)  
VIL (max) = 0.1VDD  
(OSC1, RC mode)  
VIL (max) = 0.1VDD  
(OSC1, RC mode)  
specs for more detail.  
Input High Voltage (VIH). VIH (min) = 0.36VDD  
See parameter # D040 in (I/O Ports with TTL,  
VIH (min) = 2.4V  
(I/O Ports with TTL,  
4.5V VDD 5.5V)  
VIH (min) = 2.4V  
(I/O Ports with TTL,  
4.5V VDD 5.5V)  
VIH (min) = 2.4V  
(I/O Ports with TTL,  
4.5V VDD 5.5V)  
the electrical specs for  
more detail.  
4.5V VDD 5.5V)  
Data EEPROM Memory TDEW (typ) = 10 ms  
TDEW (typ) = 10 ms  
TDEW (max) = 20 ms  
TDEW (typ) = 10 ms  
TDEW (max) = 20 ms  
TDEW (typ) = 4 ms  
TDEW (max) = 8 ms  
Erase/Write cycle time  
(TDEW). See parameter #  
D122 in the electrical  
specs for more detail.  
TDEW (max) = 20 ms  
Port Output Rise/Fall  
time (TioR, TioF). See  
parameters #20, 20A,  
TioR, TioF (max) = 25 ns TioR, TioF (max) = 35 ns TioR, TioF (max) = 35 ns TioR, TioF (max) = 35 ns  
(C84) (C84) (C84) (C84)  
TioR, TioF (max) = 60 ns TioR, TioF (max) = 70 ns TioR, TioF (max) = 70 ns TioR, TioF (max) = 70 ns  
21, and 21A in the elec- (LC84)  
trical specs for more  
detail.  
(LC84)  
(LC84)  
(LC84)  
MCLR on-chip filter. See No  
parameter #30 in the  
electrical specs for more  
detail.  
Yes  
Yes  
Yes  
PORTA and crystal oscil- For crystal oscillator con- N/A  
N/A  
N/A  
lator values less than  
500 kHz  
figurations operating  
below 500 kHz, the device  
may generate a spurious  
internal Q-clock when  
PORTA<0> switches  
state.  
RB0/INT pin  
TTL  
TTL/ST*  
TTL/ST*  
TTL/ST*  
(*Schmitt Trigger)  
(*Schmitt Trigger)  
(*Schmitt Trigger)  
DS35007C-page 78  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
TABLE 1:  
CONVERSION CONSIDERATIONS - PIC16C84, PIC16F83/F84, PIC16CR83/CR84,  
PIC16F84A (CONTINUED)  
PIC16CR83/  
Difference  
PIC16C84  
PIC16F83/F84  
PIC16F84A  
CR84  
EEADR<7:6> and IDD  
It is recommended that  
the EEADR<7:6> bits be  
cleared. When either of  
these bits is set, the maxi-  
mum IDD for the device is  
higher than when both are  
cleared.  
N/A  
N/A  
N/A  
The polarity of the  
PWRTE bit  
PWRTE  
PWRTE  
PWRTE  
PWRTE  
Recommended value of REXT = 3k- 100k  
REXT = 5k- 100k  
REXT = 5k- 100k  
REXT = 3k- 100k  
REXT for RC oscillator  
circuits  
GIE bit unintentional  
enable  
If an interrupt occurs while N/A  
the Global Interrupt  
N/A  
N/A  
Enable (GIE) bit is being  
cleared, the GIE bit may  
unintentionally be re-  
enabled by the user’s  
Interrupt Service Routine  
(the RETFIEinstruction).  
Packages  
PDIP, SOIC  
14V  
PDIP, SOIC  
12V  
PDIP, SOIC  
12V  
PDIP, SOIC, SSOP  
8.5V  
Open Drain High  
Voltage (VOD)  
2001-2013 Microchip Technology Inc.  
DS35007C-page 79  
PIC16F84A  
To convert code written for PIC16C5X to PIC16F84A,  
the user should take the following steps:  
APPENDIX C: MIGRATION FROM  
BASELINE TO  
1. Remove any program memory page select  
MID-RANGE DEVICES  
operations (PA2, PA1, PA0 bits) for CALL, GOTO.  
This section discusses how to migrate from a baseline  
device (i.e., PIC16C5X) to a mid-range device (i.e.,  
PIC16CXXX).  
2. Revisit any computed jump operations (write to  
PC or add to PC, etc.) to make sure page bits  
are set properly under the new scheme.  
The following is the list of feature improvements over  
the PIC16C5X microcontroller family:  
3. Eliminate any data memory page switching.  
Redefine data variables for reallocation.  
4. Verify all writes to STATUS, OPTION, and FSR  
registers since these have changed.  
1. Instruction word length is increased to 14-bits.  
This allows larger page sizes, both in program  
memory (2K now as opposed to 512K before)  
and the register file (128 bytes now versus  
32 bytes before).  
5. Change RESET vector to 0000h.  
2. A PC latch register (PCLATH) is added to han-  
dle program memory paging. PA2, PA1 and PA0  
bits are removed from the STATUS register and  
placed in the OPTION register.  
3. Data memory paging is redefined slightly. The  
STATUS register is modified.  
4. Four new instructions have been added:  
RETURN, RETFIE, ADDLW, and SUBLW. Two  
instructions, TRIS and OPTION, are being  
phased out, although they are kept for  
compatibility with PIC16C5X.  
5. OPTION and TRIS registers are made  
addressable.  
6. Interrupt capability is added. Interrupt vector is  
at 0004h.  
7. Stack size is increased to eight-deep.  
8. RESET vector is changed to 0000h.  
9. RESET of all registers is revisited. Five different  
RESET (and wake-up) types are recognized.  
Registers are reset differently.  
10. Wake-up from SLEEP through interrupt is  
added.  
11. Two separate timers, the Oscillator Start-up  
Timer (OST) and Power-up Timer (PWRT), are  
included for more reliable power-up. These  
timers are invoked selectively to avoid  
unnecessary delays on power-up and wake-up.  
12. PORTB has weak pull-ups and interrupt-on-  
change features.  
13. T0CKI pin is also a port pin (RA4/T0CKI).  
14. FSR is a full 8-bit register.  
15. "In system programming" is made possible. The  
user can program PIC16CXX devices using only  
five pins: VDD, VSS, VPP, RB6 (clock) and RB7  
(data in/out).  
DS35007C-page 80  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
INDEX  
DC Characteristics........................................................49, 51  
Development Support......................................................... 43  
Device Overview................................................................... 3  
A
Absolute Maximum Ratings ................................................ 47  
AC (Timing) Characteristics................................................ 53  
Architecture, Block Diagram ................................................. 3  
Assembler  
E
EECON1 Register  
MPASM Assembler..................................................... 44  
EEIF Bit ...................................................................... 29  
Electrical Characteristics .................................................... 47  
Load Conditions.......................................................... 54  
Parameter Measurement Information......................... 54  
PIC16F84A-04 Voltage-Frequency Graph ................. 48  
PIC16F84A-20 Voltage-Frequency Graph ................. 48  
PIC16LF84A-04 Voltage-Frequency Graph ............... 48  
Temperature and Voltage Specifications - AC ........... 54  
Endurance ............................................................................ 1  
Errata.................................................................................... 2  
External Clock Input (RA4/T0CKI). See Timer0  
B
Banking, Data Memory ......................................................... 6  
Block Diagrams  
Crystal/Ceramic Resonator Operation........................ 22  
External Clock Input Operation................................... 22  
External Power-on Reset Circuit................................. 26  
Interrupt Logic............................................................. 29  
On-chip Reset............................................................. 24  
PIC16F84A ................................................................... 3  
PORTA  
RA3:RA0 Pins..................................................... 15  
RA4 Pins............................................................. 15  
PORTB  
RB3:RB0 Pins..................................................... 17  
RB7:RB4 Pins..................................................... 17  
RC Oscillator Mode..................................................... 23  
Timer0......................................................................... 19  
Timer0/WDT Prescaler ............................................... 20  
Watchdog Timer (WDT).............................................. 31  
External Interrupt Input (RB0/INT). See Interrupt Sources  
External Power-on Reset Circuit......................................... 26  
F
Firmware Instructions ......................................................... 35  
I
I/O Ports ............................................................................. 15  
ID Locations..................................................................21, 33  
In-Circuit Serial Programming (ICSP)...........................21, 33  
INDF Register....................................................................... 7  
Indirect Addressing............................................................. 11  
FSR Register.............................................. 6, 7, 11, 25  
INDF Register.................................................. 7, 11, 25  
Instruction Format............................................................... 35  
Instruction Set..................................................................... 35  
ADDLW....................................................................... 37  
ADDWF ...................................................................... 37  
ANDLW....................................................................... 37  
ANDWF ...................................................................... 37  
BCF ............................................................................ 37  
BSF............................................................................. 37  
BTFSC........................................................................ 38  
BTFSS........................................................................ 37  
CALL........................................................................... 38  
CLRF .......................................................................... 38  
CLRW......................................................................... 38  
CLRWDT .................................................................... 38  
COMF......................................................................... 38  
DECF.......................................................................... 38  
DECFSZ ..................................................................... 39  
GOTO......................................................................... 39  
INCF ........................................................................... 39  
INCFSZ....................................................................... 39  
IORLW........................................................................ 39  
IORWF........................................................................ 39  
MOVF ......................................................................... 40  
MOVLW...................................................................... 40  
MOVWF...................................................................... 40  
NOP............................................................................ 40  
RETFIE....................................................................... 40  
RETLW....................................................................... 40  
RETURN..................................................................... 40  
RLF............................................................................. 41  
RRF ............................................................................ 41  
SLEEP........................................................................ 41  
SUBLW....................................................................... 41  
C
C (Carry) bit .......................................................................... 8  
C Compilers  
MPLAB C18 ................................................................ 44  
CLKIN Pin ............................................................................. 4  
CLKOUT Pin ......................................................................... 4  
Code Examples  
Clearing RAM Using Indirect Addressing.................... 11  
Data EEPOM Write Verify........................................... 14  
Indirect Addressing ..................................................... 11  
Initializing PORTA....................................................... 15  
Initializing PORTB....................................................... 17  
Reading Data EEPROM ............................................. 14  
Saving STATUS and W Registers in RAM ................. 30  
Writing to Data EEPROM............................................ 14  
Code Protection ........................................................... 21, 33  
Configuration Bits................................................................ 21  
Configuration Word ............................................................. 21  
Conversion Considerations................................................. 78  
Customer Change Notification Service ............................... 85  
Customer Notification Service............................................. 85  
Customer Support............................................................... 85  
D
Data EEPROM Memory...................................................... 13  
Associated Registers .................................................. 14  
EEADR Register ..............................................7, 13, 25  
EECON1 Register............................................7, 13, 25  
EECON2 Register............................................7, 13, 25  
EEDATA Register ............................................7, 13, 25  
Write Complete Enable (EEIE Bit) .............................. 29  
Write Complete Flag (EEIF Bit)................................... 29  
Data EEPROM Write Complete .......................................... 29  
Data Memory ........................................................................ 6  
Bank Select (RP0 Bit) ................................................... 6  
Banking......................................................................... 6  
DC bit .................................................................................... 8  
2001-2013 Microchip Technology Inc.  
DS35007C-page 81  
PIC16F84A  
SUBWF.......................................................................41  
SWAPF .......................................................................41  
XORLW.......................................................................42  
XORWF.......................................................................42  
Summary Table...........................................................36  
INT Interrupt (RB0/INT).......................................................29  
INTCON Register.................................7, 10, 18, 20, 25, 29  
EEIE Bit.......................................................................29  
GIE Bit.................................................................. 10, 29  
INTE Bit................................................................ 10, 29  
INTF Bit................................................................ 10, 29  
PEIE Bit.......................................................................10  
RBIE Bit ............................................................... 10, 29  
RBIF Bit..........................................................10, 17, 29  
T0IE Bit ................................................................ 10, 29  
T0IF Bit ..........................................................10, 20, 29  
Internet Address..................................................................85  
Interrupt Sources.......................................................... 21, 29  
Block Diagram.............................................................29  
Data EEPROM Write Complete ........................... 29, 32  
Interrupt-on-Change (RB7:RB4) ...............4, 17, 29, 32  
RB0/INT Pin, External...............................4, 18, 29, 32  
TMR0 Overflow .................................................... 20, 29  
Interrupts, Context Saving During.......................................30  
Interrupts, Enable Bits  
Data EEPROM Write Complete Enable (EEIE Bit) .....29  
Global Interrupt Enable (GIE Bit) ................................10  
Interrupt-on-Change (RB7:RB4) Enable (RBIE Bit)....10  
Peripheral Interrupt Enable (PEIE Bit) ........................10  
RB0/INT Enable (INTE Bit) .........................................10  
TMR0 Overflow Enable (T0IE Bit)...............................10  
Interrupts, Flag Bits.............................................................29  
Data EEPROM Write Complete Flag (EEIF Bit)..........29  
Interrupt-on-Change (RB7:RB4) Flag (RBIF Bit) ........10  
RB0/INT Flag (INTF Bit)..............................................10  
TMR0 Overflow Flag (T0IF Bit)...................................10  
IRP bit ...................................................................................8  
OPTION_REG Register.................................... 7, 18, 20, 25  
INTEDG Bit................................................................. 29  
PS2:PS0 Bits.............................................................. 19  
PSA Bit ....................................................................... 19  
OSC1 Pin.............................................................................. 4  
OSC2 Pin.............................................................................. 4  
Oscillator Configuration ................................................21, 22  
Block Diagram ......................................................22, 23  
Capacitor Selection for Ceramic Resonators.............. 22  
Capacitor Selection for Crystal Oscillator ................... 23  
Crystal Oscillator/Ceramic Resonators....................... 22  
HS.........................................................................22, 28  
LP .........................................................................22, 28  
Oscillator Types.......................................................... 22  
RC .................................................................22, 23, 28  
XT .........................................................................22, 28  
P
Packaging Information........................................................ 69  
Marking....................................................................... 69  
PD bit.................................................................................... 8  
Pinout Descriptions............................................................... 4  
Pointer, FSR ....................................................................... 11  
POR. See Power-on Reset  
PORTA ...........................................................................4, 15  
Associated Registers.................................................. 16  
Functions .................................................................... 16  
Initializing.................................................................... 15  
PORTA Register....................................... 7, 15, 16, 25  
RA3:RA0 Block Diagram ............................................ 15  
RA4 Block Diagram .................................................... 15  
RA4/T0CKI Pin ................................................4, 15, 19  
TRISA Register...................................7, 15, 16, 20, 25  
PORTB ...........................................................................4, 17  
Associated Registers.................................................. 18  
Functions .................................................................... 18  
Initializing.................................................................... 17  
PORTB Register....................................... 7, 17, 18, 25  
Pull-up Enable Bit (RBPU Bit)....................................... 9  
RB0/INT Edge Select (INTEDG Bit) ............................. 9  
RB0/INT Pin, External......................................4, 18, 29  
RB3:RB0 Block Diagram ............................................ 17  
RB7:RB4 Block Diagram ............................................ 17  
RB7:RB4 Interrupt-on-Change ........................4, 17, 29  
RB7:RB4 Interrupt-on-Change Enable (RBIE Bit)...... 10  
RB7:RB4 Interrupt-on-Change Flag (RBIF Bit).....10, 17  
TRISB Register......................................... 7, 17, 18, 25  
Postscaler, WDT  
Assignment (PSA Bit) ................................................... 9  
Rate Select (PS2:PS0 Bits) .......................................... 9  
Postscaler. See Prescaler  
Power-down (PD) Bit. See Power-on Reset (POR)  
Power-down Mode. See SLEEP  
Power-on Reset (POR)..........................................21, 24, 26  
Oscillator Start-up Timer (OST)............................21, 26  
PD Bit .................................................8, 24, 28, 32, 33  
Power-up Timer (PWRT) ......................................21, 26  
Time-out Sequence .................................................... 28  
Time-out Sequence on Power-up.........................27, 28  
TO Bit ..........................................8, 24, 28, 30, 32, 33  
Prescaler............................................................................. 19  
Assignment (PSA Bit) ................................................. 19  
Block Diagram ............................................................ 20  
Rate Select (PS2:PS0 Bits) ........................................ 19  
Switching Prescaler Assignment ................................ 20  
M
Master Clear (MCLR)  
MCLR Pin......................................................................4  
MCLR Reset, Normal Operation .................................24  
MCLR Reset, SLEEP........................................... 24, 32  
Memory Organization............................................................5  
Data EEPROM Memory..............................................13  
Data Memory ................................................................6  
Program Memory ..........................................................5  
Microchip Internet Web Site................................................85  
Migration from Baseline to Mid-Range Devices..................80  
MPLAB ASM30 Assembler, Linker, Librarian .....................44  
MPLAB Integrated Development Environment Software ....43  
MPLAB PM3 Device Programmer.......................................46  
MPLAB REAL ICE In-Circuit Emulator System...................45  
MPLINK Object Linker/MPLIB Object Librarian ..................44  
O
OPCODE Field Descriptions...............................................35  
OPTION Register..................................................................9  
INTEDG Bit ...................................................................9  
PS2:PS0 Bits ................................................................9  
PSA Bit..........................................................................9  
RBPU Bit.......................................................................9  
T0CS Bit........................................................................9  
T0SE Bit........................................................................9  
DS35007C-page 82  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
Prescaler, Timer0  
Assignment (PSA Bit) ................................................... 9  
Timing Conditions............................................................... 54  
Timing Diagrams  
Rate Select (PS2:PS0 Bits) .......................................... 9  
Program Counter ................................................................ 11  
PCL Register....................................................7, 11, 25  
PCLATH Register ............................................7, 11, 25  
Reset Conditions......................................................... 24  
Program Memory .................................................................. 5  
General Purpose Registers........................................... 6  
Interrupt Vector ...................................................... 5, 29  
RESET Vector............................................................... 5  
Special Function Registers ...................................... 6, 7  
Programming, Device Instructions ...................................... 35  
CLKOUT and I/O ........................................................ 56  
Diagrams and Specifications...................................... 55  
CLKOUT and I/O Requirements......................... 56  
External Clock Requirements............................. 55  
RESET, Watchdog Timer, Oscillator  
Start-up Timer and Power-up  
Timer Requirements................................... 57  
Timer0 Clock Requirements............................... 58  
External Clock ............................................................ 55  
RESET, Watchdog Timer, Oscillator Start-up  
Timer and Power-up Timer................................. 57  
Time-out Sequence on Power-up.........................27, 28  
Timer0 Clock .............................................................. 58  
Wake-up From Sleep Through Interrupt..................... 32  
Timing Parameter Symbology ............................................ 53  
TO bit.................................................................................... 8  
R
RAM. See Data Memory  
Reader Response............................................................... 86  
Register File.......................................................................... 6  
Register File Map.................................................................. 6  
Registers  
W
Configuration Word..................................................... 21  
EECON1 (EEPROM Control)...................................... 13  
INTCON ...................................................................... 10  
OPTION ........................................................................ 9  
STATUS........................................................................ 8  
Reset............................................................................ 21, 24  
Block Diagram...................................................... 24, 26  
MCLR Reset. See MCLR  
W Register....................................................................25, 30  
Wake-up from SLEEP...............................21, 26, 28, 29, 32  
Interrupts ..............................................................32, 33  
MCLR Reset............................................................... 32  
WDT Reset................................................................. 32  
Watchdog Timer (WDT)................................................21, 30  
Block Diagram ............................................................ 31  
Postscaler. See Prescaler  
Power-on Reset (POR). See Power-on Reset (POR)  
Reset Conditions for All Registers .............................. 25  
Reset Conditions for Program Counter....................... 24  
Reset Conditions for STATUS Register...................... 24  
WDT Reset. See Watchdog Timer (WDT)  
Programming Considerations..................................... 31  
RC Oscillator .............................................................. 30  
Time-out Period.......................................................... 30  
WDT Reset, Normal Operation................................... 24  
WDT Reset, SLEEP .............................................24, 32  
WWW Address ................................................................... 85  
WWW, On-Line Support ....................................................... 2  
Revision History.................................................................. 77  
RP1:RP0 (Bank Select) bits.................................................. 8  
S
Z
Saving W Register and STATUS in RAM ........................... 30  
SLEEP ............................................................21, 24, 29, 32  
Software Simulator (MPLAB SIM)....................................... 45  
Special Features of the CPU .............................................. 21  
Special Function Registers .............................................. 6, 7  
Speed, Operating.............................................. 1, 22, 23, 55  
Stack................................................................................... 11  
STATUS Register ............................................... 7, 8, 25, 30  
C Bit .............................................................................. 8  
DC Bit............................................................................ 8  
PD Bit................................................. 8, 24, 28, 32, 33  
Reset Conditions......................................................... 24  
RP0 Bit.......................................................................... 6  
TO Bit...........................................8, 24, 28, 30, 32, 33  
Z Bit............................................................................... 8  
Z (Zero) bit............................................................................ 8  
T
Time-out (TO) Bit. See Power-on Reset (POR)  
Timer0................................................................................. 19  
Associated Registers .................................................. 20  
Block Diagram............................................................. 19  
Clock Source Edge Select (T0SE Bit)........................... 9  
Clock Source Select (T0CS Bit).................................... 9  
Overflow Enable (T0IE Bit) .................................. 10, 29  
Overflow Flag (T0IF Bit).................................10, 20, 29  
Overflow Interrupt ................................................ 20, 29  
Prescaler. See Prescaler  
RA4/T0CKI Pin, External Clock .................................. 19  
TMR0 Register.................................................7, 20, 25  
2001-2013 Microchip Technology Inc.  
DS35007C-page 83  
PIC16F84A  
NOTES:  
DS35007C-page 84  
2001-2013 Microchip Technology Inc.  
THE MICROCHIP WEB SITE  
CUSTOMER SUPPORT  
Microchip provides online support via our WWW site at  
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To register, access the Microchip web site at  
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2001-2013 Microchip Technology Inc.  
DS35007C-page 85  
READER RESPONSE  
It is our intention to provide you with the best documentation possible to ensure successful use of your Microchip  
product. If you wish to provide your comments on organization, clarity, subject matter, and ways in which our  
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Device:  
Questions:  
1. What are the best features of this document?  
2. How does this document meet your hardware and software development needs?  
3. Do you find the organization of this document easy to follow? If not, why?  
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DS35007C-page 86  
2001-2013 Microchip Technology Inc.  
PIC16F84A  
PIC16F84A PRODUCT IDENTIFICATION SYSTEM  
To order or obtain information (e.g., on pricing or delivery) refer to the factory or the listed sales office.  
X
/XX  
XXX  
PART NO.  
Device  
-XX  
Examples:  
a) PIC16F84A -04/P 301 = Commercial  
temp., PDIP package, 4 MHz, normal VDD  
limits, QTP pattern #301.  
Frequency Temperature Package  
Pattern  
Range  
Range  
b) PIC16LF84A - 04I/SO = Industrial temp.,  
SOIC package, 200 kHz, Extended VDD  
limits.  
(1)  
(2)  
Device  
PIC16F84A , PIC16F84AT  
(1)  
(2)  
PIC16LF84A , PIC16LF84AT  
c) PIC16F84A - 20I/P = Industrial temp.,  
PDIP package, 20 MHz, normal VDD limits.  
Frequency Range 04  
20  
=
=
4 MHz  
20 MHz  
Temperature  
Range  
-
I
=
=
0°C to +70°C  
-40°C to +85°C  
Note 1:  
2:  
F
= Standard VDD range  
Package  
P
=
PDIP  
LF = Extended VDD range  
T
SO =  
SS  
SOIC (Gull Wing, 300 mil body)  
SSOP  
= in tape and reel - SOIC and  
SSOP packages only.  
=
Pattern  
QTP, SQTP, ROM Code (factory specified) or  
Special Requirements . Blank for OTP and  
Windowed devices.  
2001-2013 Microchip Technology Inc.  
DS35007C-page87  
PIC16F84A  
NOTES:  
DS35007C-page 88  
2001-2013 Microchip Technology Inc.  
Note the following details of the code protection feature on Microchip devices:  
Microchip products meet the specification contained in their particular Microchip Data Sheet.  
Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the  
intended manner and under normal conditions.  
There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our  
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data  
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.  
Microchip is willing to work with the customer who is concerned about the integrity of their code.  
Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not  
mean that we are guaranteeing the product as “unbreakable.”  
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our  
products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts  
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.  
Information contained in this publication regarding device  
applications and the like is provided only for your convenience  
and may be superseded by updates. It is your responsibility to  
ensure that your application meets with your specifications.  
MICROCHIP MAKES NO REPRESENTATIONS OR  
WARRANTIES OF ANY KIND WHETHER EXPRESS OR  
IMPLIED, WRITTEN OR ORAL, STATUTORY OR  
OTHERWISE, RELATED TO THE INFORMATION,  
INCLUDING BUT NOT LIMITED TO ITS CONDITION,  
QUALITY, PERFORMANCE, MERCHANTABILITY OR  
FITNESS FOR PURPOSE. Microchip disclaims all liability  
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devices in life support and/or safety applications is entirely at  
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conveyed, implicitly or otherwise, under any Microchip  
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Trademarks  
The Microchip name and logo, the Microchip logo, dsPIC,  
FlashFlex, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro,  
PICSTART, PIC logo, rfPIC, SST, SST Logo, SuperFlash  
and UNI/O are registered trademarks of Microchip Technology  
Incorporated in the U.S.A. and other countries.  
32  
FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor,  
MTP, SEEVAL and The Embedded Control Solutions  
Company are registered trademarks of Microchip Technology  
Incorporated in the U.S.A.  
Silicon Storage Technology is a registered trademark of  
Microchip Technology Inc. in other countries.  
Analog-for-the-Digital Age, Application Maestro, BodyCom,  
chipKIT, chipKIT logo, CodeGuard, dsPICDEM,  
dsPICDEM.net, dsPICworks, dsSPEAK, ECAN,  
ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial  
Programming, ICSP, Mindi, MiWi, MPASM, MPF, MPLAB  
Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code  
Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit,  
PICtail, REAL ICE, rfLAB, Select Mode, SQI, Serial Quad I/O,  
Total Endurance, TSHARC, UniWinDriver, WiperLock, ZENA  
and Z-Scale are trademarks of Microchip Technology  
Incorporated in the U.S.A. and other countries.  
SQTP is a service mark of Microchip Technology Incorporated  
in the U.S.A.  
GestIC and ULPP are registered trademarks of Microchip  
Technology Germany II GmbH & Co. & KG, a subsidiary of  
Microchip Technology Inc., in other countries.  
All other trademarks mentioned herein are property of their  
respective companies.  
© 2001-2013, Microchip Technology Incorporated, Printed in  
the U.S.A., All Rights Reserved.  
Printed on recycled paper.  
ISBN: 9781620769409  
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Tempe, Arizona; Gresham, Oregon and design centers in California  
and India. The Company’s quality system processes and procedures  
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping  
devices, Serial EEPROMs, microperipherals, nonvolatile memory and  
analog products. In addition, Microchip’s quality system for the design  
and manufacture of development systems is ISO 9001:2000 certified.  
== ISO/TS 16949 ==  
2001-2013 Microchip Technology Inc.  
DS35007C-page 89  
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Tel: 86-21-5407-5533  
Fax: 86-21-5407-5066  
Singapore  
Tel: 65-6334-8870  
Fax: 65-6334-8850  
Indianapolis  
Noblesville, IN  
Tel: 317-773-8323  
Fax: 317-773-5453  
China - Shenyang  
Tel: 86-24-2334-2829  
Fax: 86-24-2334-2393  
Taiwan - Hsin Chu  
Tel: 886-3-5778-366  
Fax: 886-3-5770-955  
Los Angeles  
China - Shenzhen  
Tel: 86-755-8864-2200  
Fax: 86-755-8203-1760  
Taiwan - Kaohsiung  
Tel: 886-7-213-7828  
Fax: 886-7-330-9305  
Mission Viejo, CA  
Tel: 949-462-9523  
Fax: 949-462-9608  
China - Wuhan  
Tel: 86-27-5980-5300  
Fax: 86-27-5980-5118  
Taiwan - Taipei  
Tel: 886-2-2508-8600  
Fax: 886-2-2508-0102  
Santa Clara  
Santa Clara, CA  
Tel: 408-961-6444  
Fax: 408-961-6445  
China - Xian  
Tel: 86-29-8833-7252  
Fax: 86-29-8833-7256  
Thailand - Bangkok  
Tel: 66-2-694-1351  
Fax: 66-2-694-1350  
Toronto  
Mississauga, Ontario,  
Canada  
China - Xiamen  
Tel: 905-673-0699  
Fax: 905-673-6509  
Tel: 86-592-2388138  
Fax: 86-592-2388130  
China - Zhuhai  
Tel: 86-756-3210040  
Fax: 86-756-3210049  
11/29/12  
DS35007C-page 90  
2001-2013 Microchip Technology Inc.  

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