DS2250T-8-16 [DALLAS]

Soft Microcontroller Module; 软微控制器模块
DS2250T-8-16
型号: DS2250T-8-16
厂家: DALLAS SEMICONDUCTOR    DALLAS SEMICONDUCTOR
描述:

Soft Microcontroller Module
软微控制器模块

微控制器和处理器 外围集成电路 装置 时钟
文件: 总20页 (文件大小:596K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
DS2250(T)  
Soft Microcontroller Module  
www.dalsemi.com  
FEATURES  
8-bit 8051-compatible microcontroller adapts  
to task-at-hand:  
PIN ASSIGNMENT  
-
-
-
8, 32, or 64 kbytes of nonvolatile RAM  
for program and/or data memory storage  
Initial downloading of software in end  
system via on-chip serial port  
Capable of modifying its own program  
and/or data memory in end use  
1
20  
21  
40  
40-Pin SIMM  
High-reliability operation:  
-
Maintains all nonvolatile resources for 10  
years in the absence of VCC  
Power-fail reset  
Early warning power-fail interrupt  
Watchdog timer  
-
-
-
Software Security Feature:  
-
Executes encrypted software to prevent  
unauthorized disclosure  
On-chip, full-duplex serial I/O ports  
Two on-chip timer/event counters  
32 parallel I/O lines  
Compatible with industry standard 8051  
instruction set  
Permanently powered real time clock  
DESCRIPTION  
The DS2250(T) Soft Microcontroller Module is a fully 8051-compatible 8-bit CMOS microcontroller that  
offers “softness” in all aspects of its application. This is accomplished through the comprehensive use of  
nonvolatile technology to preserve all information in the absence of system VCC. The internal  
program/data memory space is implemented using 8, 32, or 64 kbytes of nonvolatile CMOS SRAM.  
Furthermore, internal data registers and key configuration registers are also nonvolatile. An optional real  
time clock gives permanently powered timekeeping. The clock keeps time to a hundredth of a second  
using an on-board crystal. All nonvolatile memory and resources are maintained for over 10 years at  
room temperature in the absence of power.  
1 of 20  
112099  
DS2250(T)  
ORDERING INFORMATION  
MAX CRYSTAL  
SPEED  
PART NUMBER  
RAM SIZE  
TIMEKEEPING?  
DS2250-8-16  
8 kbytes  
32 kbytes  
64 kbytes  
8 kbytes  
16 MHz  
16 MHz  
16 MHz  
16 MHz  
16 MHz  
16 MHz  
No  
No  
DS2250-32-16  
DS2250-64-16  
DS2250T-8-16  
DS2250T-32-16  
DS2250T-64-16  
No  
Yes  
Yes  
Yes  
32 kbytes  
64 kbytes  
Operating information is contained in the User’s Guide section of the Secure Microcontroller Data Book.  
This data sheet provides ordering information, pinout, and electrical specifications.  
2 of 20  
DS2250(T)  
DS2250(T) BLOCK DIAGRAM Figure 1  
3 of 20  
DS2250(T)  
PIN DESCRIPTION  
PIN  
DESCRIPTION  
1, 3, 5, 7, 9, P1.0 - P1.7. General purpose I/O Port 1  
11, 13, 15  
17  
RST - Active high reset input. A logic 1 applied to this pin will activate a reset state.  
This pin is pulled down internally so this pin can be left unconnected if not used. An  
RC power-on reset circuit is not needed and is not recommended.  
19  
21  
23  
25  
P3.0 RXD. General purpose I/O port pin 3.0. Also serves as the receive signal for the  
on board UART. This pin should not be connected directly to a PC COM port.  
P3.1 TXD. General purpose I/O port pin 3.1. Also serves as the transmit signal for the  
on board UART. This pin should not be connected directly to a PC COM port.  
P3.2 INT0 . General purpose I/O port pin 3.2. Also serves as the active low External  
Interrupt 0.  
P3.3 INT1 . General purpose I/O port pin 3.3. Also serves as the active low External  
Interrupt 1.  
27  
29  
31  
P3.4 T0. General purpose I/O port pin 3.4. Also serves as the Timer 0 input.  
P3.5 T1. General purpose I/O port pin 3.5. Also serves as the Timer 1 input.  
P3.6 WR . General purpose I/O port pin. Also serves as the write strobe for Expanded  
bus operation.  
33  
35, 37  
39  
P3.7 RD . General purpose I/O port pin. Also serves as the read strobe for Expanded  
bus operation.  
XTAL2, XTAL1. Used to connect an external crystal to the internal oscillator.  
XTAL1 is the input to an inverting amplifier and XTAL2 is the output.  
GND - Logic ground.  
26, 28, 30, 32, P2.7-P2.0. General purpose I/O Port 2. Also serves as the MSB of the Expanded  
34, 36, 38, 40 Address bus.  
24  
PSEN - Program Store Enable. This active low signal is used to enable an external  
program memory when using the Expanded bus. It is normally an output and should  
be unconnected if not used. PSEN also is used to invoke the Bootstrap Loader. At this  
time, PSEN will be pulled down externally. This should only be done once the  
DS2250(T) is already in a reset state. The device that pulls down should be open-drain  
since it must not interfere with PSEN under normal operation.  
22  
20  
ALE - Address Latch Enable. Used to de-multiplex the multiplexed Expanded  
Address/Data bus on Port 0. This pin is normally connected to the clock input on a  
’373 type transparent latch. When using a parallel programmer, this pin also assumes  
the PROG function for programming pulses.  
EA - External Access. This pin forces the DS2250(T) to behave like an 8031. No  
internal memory (or clock) will be available when this pin is at a logic low. Since this  
pin is pulled down internally, it should be connected to +5V to use NV RAM. In a  
parallel programmer, this pin also serves as VPP for super voltage pulses.  
4, 6, 8, 10, 12, P0.0-P0.7. General purpose I/O Port 0. This port is open-drain and can not drive a  
14, 16, 18  
logic 1. It requires external pullups. Port 0 is also the multiplexed Expanded  
Address/Data bus. When used in this mode, it does not require pullups.  
2
VCC + - 5 volts.  
4 of 20  
DS2250(T)  
INSTRUCTION SET  
The DS2250(T) executes an instruction set which is object code-compatible with the industry standard  
8051 microcontroller. As a result, software development packages which have been written for the 8051  
are compatible with the DS2250(T), including cross-assemblers, high-level language compilers, and  
debugging tools. Note that the DS2250(T) is functionally identical to the DS5000(T) except for package  
and the 64k memory option.  
A complete description for the DS2250(T) instruction set is available in the User’s Guide section of the  
Secure Microcontroller Data Book.  
MEMORY ORGANIZATION  
Figure 2 illustrates the address spaces which are accessed by the DS2250(T). As illustrated in the figure,  
separate address spaces exist for program and data memory. Since the basic addressing capability of the  
machine is 16 bits, a maximum of 64 kbytes of program memory and 64 kbytes of data memory can be  
accessed by the DS2250(T) CPU. The 8- or 32-kbyte RAM area inside of the DS2250(T) can be used to  
contain both program and data memory. A second 32k RAM is available for data only.  
The Real Time Clock (RTC) in the DS2250(T) is reached in the memory map by setting a SFR bit. The  
MCON.2 bit (ECE2) is used to select an alternate data memory map. While ECE2=1, all MOVXs will be  
routed to this alternate memory map. The real time clock is a serial device that resides in this area. A full  
description of the RTC access and example software is given in the User’s Guide section of the Secure  
Microcontroller Data Book.  
5 of 20  
DS2250(T)  
DS2250(T) MEMORY MAP Figure 2  
DATA MEMORY (MOVX)  
PROGRAM LOADING  
The Program Load Modes allow initialization of the NV RAM Program/Data Memory. This initialization  
may be performed in one of two ways:  
1. Serial Program Loading which is capable of performing Bootstrap Loading of the DS2250(T). This  
feature allows the loading of the application program to be delayed until the DS2250(T) is installed in  
the end system.  
2. Parallel Program Load cycles which perform the initial loading from parallel address/data information  
presented on the I/O port pins. This mode is timing set-compatible with the 87C51H microcontroller  
programming mode.  
The DS2250(T) is placed in its Program Load configuration by simultaneously applying a logic 1 to the  
RST pin and forcing the PSEN line to a logic 0 level. Immediately following this action, the DS2250(T)  
will look for a parallel Program Load pulse, or a serial ASCII carriage return (0DH) character received at  
9600, 2400, 1200, or 300 bps over the serial port.  
The hardware configurations used to select these modes of operation are illustrated in Figure 3.  
6 of 20  
DS2250(T)  
PROGRAM LOADING CONFIGURATIONS Figure 3  
SERIAL BOOTSTRAP LOADER  
The Serial Program Load Mode is the easiest, fastest, most reliable, and most complete method of  
initially loading application software into the DS2250(T) nonvolatile RAM. Communication can be  
performed over a standard asynchronous serial communications port. A typical application would use a  
simple RS232C serial interface to program the DS2250(T) as a final production procedure. The hardware  
configuration which is required for the Serial Program Load Mode is illustrated in Figure 3. Port pins 2.7  
and 2.6 must be either open or pulled high to avoid placing the device in a parallel load cycle. Although  
an 11.0592 MHz crystal is shown in Figure 3, a variety of crystal frequencies and loader baud rates are  
supported, shown in Table 2. The serial loader is designed to operate across a 3-wire interface from a  
standard UART. The receive, transmit, and ground wires are all that are necessary to establish  
communication with the DS2250(T).  
The Serial Bootstrap Loader implements an easy-to-use command line interface which allows an  
application program in an Intel hex representation to be loaded into and read back from the device. Intel  
hex is the typical format which existing 8051 cross-assemblers output. The serial loader responds to  
single character commands which are summarized below:  
7 of 20  
DS2250(T)  
COMMAND  
FUNCTION  
C
D
F
K
L
Return CRC-16 checksum of embedded RAM  
Dump Intel hex File  
Fill embedded RAM block with constant  
Load 40-bit encryption key  
Load Intel hex file  
R
T
U
V
W
Z
Read MCON register  
Trace (Echo) incoming Intel hex data  
Clear Security Lock  
Verify Embedded RAM with incoming Intel hex  
Write MCON register  
Set security lock  
P
Put a value to a port  
G
Get a value from a port  
Table 1 summarizes the selection of the available Parallel Program Load cycles. The timing associated  
with these cycles is illustrated in the electrical specs.  
PARALLEL PROGRAM LOAD CYCLES Table 1  
MODE  
RST  
P2.7  
P2.6  
P2.5  
X
X
X
0
PSEN  
PROG  
EA  
VPP  
VPP  
1
Program  
1
1
1
1
1
1
1
0
0
X
0
0
0
0
0
0
X
0
1
0
1
1
1
0
0
0
0
0
0
1
0
1
1
1
1
Security Set  
Verify  
Prog Expanded  
VPP  
1
Verify Expanded  
Prog MCON or Key registers  
Verify MCON registers  
0
VPP  
1
1
1
The Parallel Program cycle is used to load a byte of data into a register or memory location within the  
DS2250(T). The Verify cycle is used to read this byte back for comparison with the originally loaded  
value to verify proper loading. The Security Set cycle may be used to enable and the software security  
feature. One may also enter bytes for the MCON register or for the five encryption registers using the  
Program MCON cycle. When using this cycle, the absolute register address must be presented at Ports 1  
and 2 as in the normal program cycle (Port 2 should be 00H). The MCON contents can likewise be  
verified using the Verify MCON cycle.  
When the DS2250(T) first detects a Parallel Program Strobe pulse or a Security Set Strobe pulse while in  
the Program Load Mode following a power-on reset, the internal hardware of the device is initialized so  
that an existing 4-kbyte program can be programmed into a DS2250(T) with little or no modification.  
This initialization automatically sets the range address for 8 kbytes and maps the lowest 4-kbyte bank of  
embedded RAM as program memory. The next 4 kbytes of embedded RAM are mapped as data memory.  
In order to program more than 4 kbytes of program code, the Program/Verify Expanded cycles can be  
used. Up to 32 kbytes of program code can be entered and verified. Note that the expanded 32 kbyte  
Program/Verify cycles take much longer than the normal 4 kbyte Program/Verify cycles.  
8 of 20  
DS2250(T)  
A typical parallel loading session would follow this procedure. First, set the contents of the MCON  
register with the correct range and partition only if using expanded programming cycles. Next, the  
encryption registers can be loaded to enable encryption of the program/data memory (not required). Then,  
program the DS2250(T) using either normal or expanded program cycles and check the memory contents  
using Verify cycles. The last operation would be to turn on the security lock feature by either a Security  
Set cycle or by explicitly writing to the MCON register and setting MCON.0 to a 1.  
SERIAL LOADER BAUD RATES FOR  
DIFFERENT CRYSTAL FREQUENCIES Table 2  
BAUD RATE  
CRYSTAL FREQ  
(MHz)  
300  
1200  
Y
2400 9600  
19200  
Y
57600  
14.7456  
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
11.0592  
9.21600  
7.37280  
5.52960  
1.84320  
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
Y
ADDITIONAL INFORMATION  
A complete description for all operational aspects of the DS2250(T) is provided in the User’s Guide  
section of the Secure Microcontroller Data Book.  
DEVELOPMENT SUPPORT  
Dallas Semiconductor offers a kit package for developing and testing user code. The DS5000TK  
Evaluation Kit allows the user to download Intel hex formatted code directly to the DS2250(T) from a  
PC-XT/AT or compatible computer. The kit consists of a DS5000T-32-12, an interface pod, demo  
software, and an RS232 connector that attaches to the COM1 or COM2 serial port of a PC. The kit can be  
used with a DS2250(T). A mechanical adapter, the DS9075-40V, allows a DS2250(T) to be used in the  
DS5000TK. See the Secure microcontroller User’s Guide for further details.  
9 of 20  
DS2250(T)  
ABSOLUTE MAXIMUM RATINGS*  
Voltage on Any Pin Relative to Ground  
Operating Temperature  
-0.3V to +7.0V  
0°C to 70°C  
Storage Temperature  
Soldering Temperature  
-40°C to +70°C  
260°C for 10 seconds  
* This is a stress rating only and functional operation of the device at these or any other conditions  
above those indicated in the operation sections of this specification is not implied. Exposure to  
absolute maximum rating conditions for extended periods of time may affect reliability.  
DC CHARACTERISTICS  
PARAMETER  
(tA=0°C to70°C; VCC=5V ± 5%)  
SYMBOL MIN  
TYP  
MAX  
UNITS NOTES  
Input Low Voltage  
VIL  
VIH1  
VIH2  
VOL1  
-0.3  
2.0  
3.5  
+0.8  
V
V
V
V
1
1
1
Input High Voltage  
VCC+0.3  
VCC+0.3  
0.45  
Input High Voltage RST, XTAL1  
Output Low Voltage  
@ IOL=1.6 mA (Ports 1, 2, 3)  
0.15  
0.15  
4.8  
Output Low Voltage  
@ IOL=3.2 mA (Ports 0, ALE, PSEN )  
VOL2  
VOH1  
VOH2  
IIL  
0.45  
V
V
V
1
1
1
Output High Voltage  
@ IOH=-80 µA (Ports 1, 2, 3)  
2.4  
2.4  
Output High Voltage  
@ IOH=-400 µA (Ports 0, ALE, PSEN )  
4.8  
Input Low Current VIN = 0.45V  
(Ports 1, 2, 3)  
-50  
-500  
±10  
µA  
µA  
µA  
Transition Current; 1 to 0  
VIN=2.0V (Ports 1, 2, 3)  
ITL  
Input Leakage Current  
IL  
0.45 < VIN < VCC (Port 0)  
RRE  
ISM  
40  
125  
80  
RST, EA Pulldown Resistor  
Stop Mode Current  
kΩ  
µA  
V
4
1
1
1
Power Fail Warning Voltage  
Minimum Operating Voltage  
VPFW  
VCCmin  
VPP  
4.15  
4.05  
12.5  
4.6  
4.5  
4.75  
4.65  
13  
V
Programming Supply Voltage  
(Parallel Program Mode)  
V
Program Supply Current  
IPP  
15  
20  
mA  
mA  
Operating Current DS2250-8k  
DS2250-32k @ 12 MHz  
DS2250(T)-64-16 @ 16 MHz  
ICC  
43  
48  
54  
2
3
Idle Mode Current @ 8 MHz  
ICC  
6.2  
mA  
10 of 20  
DS2250(T)  
AC CHARACTERISTICS: EXPANDED  
BUS MODE TIMING SPECIFICATIONS  
(tA=0°C to70°C; VCC=5V ± 5%)  
#
1
2
3
4
5
PARAMETER  
SYMBOL  
1/tCLK  
MIN  
MAX  
UNITS  
MHz  
ns  
Oscillator Frequency  
1.0  
16 (-16)  
ALE Pulse Width  
tALPW  
2tCLK -40  
tCLK -40  
tCLK -35  
Address Valid to ALE Low  
Address Hold After ALE Low  
ALE Low to Valid Instr. In  
tAVALL  
tAVAAV  
tALLVI  
ns  
ns  
@ 12 MHz  
@ 16 MHz  
4tCLK -150  
4tCLK -90  
ns  
6
7
8
tALLPSL  
tPSPW  
tCLK -25  
ns  
ns  
ALE Low to PSEN Low  
PSEN Pulse Width  
3tCLK -35  
tPSLVI  
3tCLK -150  
3tCLK -90  
ns  
ns  
PSEN Low to Valid Instr. In  
@ 12 MHz  
@ 16 MHz  
9
tPSIV  
tPSIX  
tPSAV  
tAVVI  
0
ns  
ns  
ns  
Input Instr. Hold after PSEN Going High  
Input Instr. Float after PSEN Going High  
Address Hold after PSEN Going High  
10  
11  
tCLK -20  
tCLK -8  
12 Address Valid to Valid Instr. In @ 12 MHz  
@ 16 MHz  
5tCLK -150  
5tCLK -90  
ns  
ns  
13  
14  
15  
16  
tPSLAZ  
tRDPW  
tWRPW  
tRDLDV  
0
ns  
ns  
ns  
PSEN Low to Address Float  
RD Pulse Width  
6tCLK -100  
6tCLK -100  
WR Pulse Width  
5tCLK -165  
5tCLK -105  
ns  
ns  
RD Low to Valid Data In  
@ 12 MHz  
@ 16 MHz  
17  
18  
tRDHDV  
tRDHDZ  
tALLVD  
0
ns  
ns  
Data Hold after RD High  
Data Float after RD High  
2tCLK -70  
19 ALE Low to Valid Data In  
@ 12 MHz  
@ 16 MHz  
8CLK -150  
8tCLK -90  
ns  
ns  
20 Valid Addr. to Valid Data In  
@ 12 MHz  
@ 16 MHz  
tAVDV  
9tCLK -165  
9tCLK -105  
ns  
ns  
21  
22  
23  
24  
tALLRDL  
tAVRDL  
tDVWRL  
tDVWRH  
3tCLK -50  
4tCLK -130  
tCLK -60  
3tCLK +50  
ns  
ns  
ns  
ALE Low to RD or WR Low  
Address Valid to RD or WR Low  
Data Valid to WR Going Low  
7tCLK -150  
7tCLK -90  
ns  
ns  
Data Valid to WR High  
@ 12 MHz  
@ 16 MHz  
25  
26  
27  
tWRHDV  
tRDLAZ  
tCLK -50  
ns  
ns  
ns  
Data Valid after WR High  
RD Low to Address Float  
RD or WR High to ALE High  
0
tRDHALH  
tCLK -40  
tCLK +50  
11 of 20  
DS2250(T)  
EXPANDED PROGRAM MEMORY READ CYCLE  
EXPANDED DATA MEMORY READ CYCLE  
12 of 20  
DS2250(T)  
EXPANDED DATA MEMORY WRITE CYCLE  
EXTERNAL CLOCK TIMING  
13 of 20  
DS2250(T)  
AC CHARACTERISTICS (cont'd)  
EXTERNAL CLOCK DRIVE  
(tA=0°C to70°C; VCC=5V ± 5%)  
#
PARAMETER  
SYMBOL  
MIN  
MAX  
UNITS  
28 External Clock High Time  
29 External Clock Low Time  
30 External Clock Rise Time  
31 External Clock Fall Time  
@ 12 MHz  
@ 16 MHz  
tCLKHPW  
20  
15  
ns  
ns  
@ 12 MHz  
@ 16 MHz  
tCLKLPW  
tCLKR  
20  
15  
ns  
ns  
@ 12 MHz  
@ 16 MHz  
20  
15  
ns  
ns  
@ 12 MHz  
@ 16 MHz  
tCLKF  
20  
15  
ns  
ns  
AC CHARACTERISTICS (cont'd)  
SERIAL PORT TIMING - MODE 0  
(tA=0°C to70°C; VCC=5V ± 5%)  
#
PARAMETER  
SYMBOL  
tSPCLK  
MIN  
MAX  
UNITS  
35 Serial Port Cycle Time  
12tCLK  
µs  
36 Output Data Setup to Rising Clock Edge  
37 Output Data Hold after Rising Clock Edge  
38 Clock Rising Edge to Input Data Valid  
39 Input Data Hold after Rising Clock Edge  
tDOCH  
10tCLK -133  
2tCLK -117  
ns  
tCHDO  
ns  
tCHDV  
10tCLK -133  
ns  
tCHDIV  
0
ns  
SERIAL PORT TIMING - MODE 0  
14 of 20  
DS2250(T)  
AC CHARACTERISTICS (cont'd)  
POWER CYCLING TIMING  
(tA=0°C to70°C; VCC=5V ± 5%)  
#
PARAMETER  
SYMBOL  
MIN  
MAX  
UNITS  
32 Slew Rate from VCCmin to 3.3V  
33 Crystal Start-up Time  
tF  
40  
µs  
tCSU  
tPOR  
(note 5)  
21504  
34 Power-On Reset Delay  
tCLK  
POWER CYCLE TIMING  
15 of 20  
DS2250(T)  
AC CHARACTERISTICS (cont'd)  
PARALLEL PROGRAM LOAD TIMING  
(tA=0°C to70°C; VCC=5V ± 5%)  
#
PARAMETER  
SYMBOL  
1/tCLK  
MIN  
MAX  
UNITS  
40 Oscillator Frequency  
1.0  
12.0  
MHz  
41  
42  
43  
44  
tAVPRL  
tPRHAV  
tDVPRL  
tPRHDV  
tP27HVP  
tVPHPRL  
tPRHVPL  
tPRW  
0
Address Setup to PROG Low  
Address Hold after PROG High  
Data Setup to PROG Low  
0
0
0
0
Data Hold after PROG High  
45 P2.7, 2.6, 2.5 Setup to VPP  
46  
47  
48  
0
VPP Setup to PROG Low  
VPP Hold after PROG Low  
PROG Width Low  
0
2400  
tCLK  
tCLK  
49 Data Output from Address Valid  
50 Data Output from P2.7 Low  
51 Data Float after P2.7 High  
tAVDV  
48  
1800*  
tDVP27L  
tP27HDZ  
48  
1800*  
tCLK  
tCLK  
0
48  
1800*  
52  
53  
tPORPV  
tRAVPH  
21504  
1200  
tCLK  
tCLK  
Delay to Reset/ PSEN Active after Power On  
Reset/ PSEN Active (or Verify Inactive) to  
VPP High  
54 VPP Inactive (Between Program Cycles)  
55 Verify Active Time  
tVPPPC  
tVFT  
1200  
tCLK  
tCLK  
48  
2400*  
* Second set of numbers refers to expanded memory programming up to 32k bytes.  
16 of 20  
DS2250(T)  
PARALLEL PROGRAM LOAD TIMING  
CAPACITANCE  
(test frequency=1MHz; tA=25°C)  
PARAMETER  
SYMBOL MIN  
TYP  
MAX  
UNITS NOTES  
Output Capacitance  
Input Capacitance  
CO  
CI  
10  
pF  
pF  
10  
17 of 20  
DS2250(T)  
DS2250(T) TYPICAL ICC VS. FREQUENCY  
FREQUENCY OF OPERATION (MHz)  
(VCC=+5V, tA=25°C)  
Normal operation is measured using:  
1) External crystals on XTAL1 and 2  
2) All port pins disconnected  
3) RST=0 volts and EA=VCC  
4) Part performing endless loop writing to internal memory  
Idle mode operation is measured using:  
1) External clock source at XTAL1; XTAL2 floating  
2) All port pins disconnected  
3) RST=0 volts and EA=VCC  
4) Part set in IDLE mode by software  
NOTES:  
1. All voltages are referenced to ground.  
2. Maximum operating ICC is measured with all output pins disconnected; XTAL1 driven with tCLKR  
,
,
tCLKF = 10 ns, VIL = 0.5V; XTAL2 disconnected; EA = RST = PORT0 = VCC.  
3. Idle mode ICC is measured with all output pins disconnected; XTAL1 driven at 8 MHz with tCLKR  
tCLKF = 10 ns, VIL = 0.5V; XTAL2 disconnected; EA = PORT0 = VCC, RST = VSS.  
4. Stop mode ICC is measured with all output pins disconnected; EA = PORT0 = VCC; XTAL2 not  
connected; RST = VSS.  
5. Crystal start-up time is the time required to get the mass of the crystal into vibrational motion from  
the time that power is first applied to the circuit until the first clock pulse is produced by the on-chip  
oscillator. The user should check with the crystal vendor for the worst case spec on this time.  
18 of 20  
DS2250(T)  
PACKAGE DRAWING  
PKG  
DIM  
A
INCHES  
MIN  
MAX  
2.655  
2.389  
0.855  
0.405  
0.255  
2.645  
2.379  
0.845  
0.395  
0.245  
B
C
D
E
F
0.050 BSC  
G
H
0.075  
0.245  
0.085  
0.255  
I
0.950 BSC  
J
0.120  
1.320  
1.445  
0.057  
-
0.130  
1.330  
1.455  
0.067  
0.160  
0.195  
0.054  
K
L
M
N
O
P
-
0.047  
19 of 20  
DS2250(T)  
DATA SHEET REVISION SUMMARY  
The following represent the key differences between 12/13/95 and 08/16/96 version of the DS2250(T)  
data sheet. Please review this summary carefully.  
1. Correct Figure 3 to show RST active high.  
2. Add minimum value to PCB thickness.  
20 of 20  

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