XR16M564IJ-0A-EVB [EXAR]

EVAL BOARD FOR XR16M654-A 68PLCC;
XR16M564IJ-0A-EVB
型号: XR16M564IJ-0A-EVB
厂家: EXAR CORPORATION    EXAR CORPORATION
描述:

EVAL BOARD FOR XR16M654-A 68PLCC

文件: 总55页 (文件大小:1080K)
中文:  中文翻译
下载:  下载PDF数据表文档文件
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
MAY 2008  
REV. 1.0.0  
FEATURES  
GENERAL DESCRIPTION  
Pin-to-pin compatible with ST16C454, ST16C554,  
TI’s TL16C754B and NXP’s SC16C754B  
1
The XR16M564 (M564) is an enhanced quad  
Universal Asynchronous Receiver and Transmitter  
(UART) with 32 bytes of transmit and receive FIFOs,  
programmable transmit and receive FIFO trigger  
levels, automatic hardware and software flow control,  
and data rates of up to 16 Mbps at 4X sampling rate.  
Each UART has a set of registers that provide the  
user with operating status and control, receiver error  
indications, and modem serial interface controls. An  
internal loopback capability allows onboard  
diagnostics. The M564 is available in a 48-pin QFN,  
64-pin LQFP, 68-pin PLCC and 80-pin LQFP  
packages. The 64-pin and 80-pin packages only offer  
the 16 mode interface, but the 48 and 68 pin  
packages offer an additional 68 mode interface which  
allows easy integration with Motorola processors.  
The XR16M564IV (64-pin) offers three state interrupt  
output while the XR16M564DIV provides continuous  
interrupt output. The XR16M564 is compatible with  
the industry standard ST16C554 and ST16C654/  
654D.  
Intel or Motorola Data Bus Interface select  
Four independent UART channels  
Register Set Compatible to 16C550  
Data rates of up to 16 Mbps  
32 byte Transmit FIFO  
32 byte Receive FIFO with error tags  
4 Selectable TX and RX FIFO Trigger Levels  
Automatic Hardware (RTS/CTS) Flow Control  
Automatic Software (Xon/Xoff) Flow Control  
Programmable Xon/Xoff characters  
Wireless Infrared (IrDA 1.0) Encoder/Decoder  
Full modem interface  
1.62V to 3.63V supply operation  
Sleep Mode with automatic wake-up  
Crystal oscillator or external clock input  
NOTE: 1 Covered by U.S. Patent #5,649,122.  
APPLICATIONS  
Portable Appliances  
Telecommunication Network Routers  
Ethernet Network Routers  
Cellular Data Devices  
Factory Automation and Process Controls  
F
IGURE 1. XR16M564 BLOCK DIAGRAM  
1.62V to 3.6V VCC  
GND  
A2:A0  
D7:D0  
UART Channel A  
32 Byte TX FIFO  
IOR#  
IOW#  
CSA#  
CSB#  
UART  
Regs  
TXA, RXA, DTRA#,  
DSRA#, RTSA#, CTSA#,  
CDA#, RIA#  
IR  
TX & RX  
ENDEC  
BRG  
32 Byte RX FIFO  
CSC#  
CSD#  
TXB, RXB, DTRB#,  
DSRB#, RTSB#, CTSB#,  
CDB#, RIB#  
UART Channel B  
(same as Channel A)  
INTA  
INTB  
INTC  
Data Bus  
Interface  
TXC, RXC, DTRC#,  
DSRC#, RTSC#, CTSC#,  
CDC#, RIC#  
UART Channel C  
(same as Channel A)  
INTD  
TXRDY# A-D  
RXRDY# A-D  
Reset  
TXD, RXD, DTRD#,  
DSRD#, RTSD#, CTSD#,  
CDD#, RID#  
UART Channel D  
(same as Channel A)  
16/68#  
INTSEL  
CLKSEL  
XTAL1  
XTAL2  
Crystal Osc/Buffer  
564 BLK  
Exar Corporation 48720 Kato Road, Fremont CA, 94538 (510) 668-7000 FAX (510) 668-7017 www.exar.com  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
F
IGURE 2. PIN  
O
UT  
A
SSIGNMENT  
F
OR 68-PIN PLCC PACKAGES  
IN  
16 AND 68 MODE AND 64-PIN LQFP PACKAGES  
DSRA# 10  
60 DSRD#  
60  
59  
58  
DSRD#  
CTSD#  
DTRD#  
DSRA# 10  
CTSA# 11  
DTRA# 12  
VCC 13  
CTSA# 11  
59 CTSD#  
DTRA# 12  
58 DTRD#  
VCC 13  
57 GND  
57 GND  
RTSA# 14  
56 RTSD#  
56  
RTSD#  
RTSA# 14  
INTA 15  
CSA# 16  
TXA 17  
IRQ# 15  
55 INTD  
55 N.C.  
54 N.C.  
53 TXD  
52 N.C.  
51 TXC  
50 A4  
49 N.C.  
CS# 16  
54 CSD#  
XR16M564  
68-pin PLCC  
Motorola Mode  
XR16M564  
68-pin PLCC  
Intel Mode  
TXA 17  
53 TXD  
R/W# 18  
52 IOR#  
IOW# 18  
TXB 19  
TXB 19  
51 TXC  
(16/68# pin connected to GND)  
(16/68# pin connected to VCC)  
A3 20  
N.C. 21  
CSB# 20  
INTB 21  
RTSB# 22  
GND 23  
50 CSC#  
49 INTC  
RTSB# 22  
GND 23  
48  
RTSC#  
48 RTSC#  
47 VCC  
47 VCC  
DTRB# 24  
CTSB# 25  
DSRB# 26  
46  
45  
44  
DTRC#  
DTRB# 24  
CTSB# 25  
DSRB# 26  
46 DTRC#  
45 CTSC#  
44 DSRC#  
CTSC#  
DSRC#  
1
2
48  
47  
46  
45  
44  
43  
42  
41  
40  
39  
38  
37  
36  
35  
34  
33  
DSRD#  
CTSD#  
DTRD#  
GND  
DSRA#  
CTSA#  
DTRA#  
VCC  
3
4
RTSA#  
INTA  
5
RTSD#  
INTD  
6
CSA#  
TXA  
7
CSD#  
TXD  
XR16M564  
64-pin TQFP  
Intel Mode Only  
8
IOR#  
IOW#  
TXB  
9
TXC  
10  
11  
12  
13  
14  
15  
16  
CSC#  
INTC  
CSB#  
INTB  
RTSC#  
VCC  
RTSB#  
GND  
DTRB#  
CTSB#  
DTRC#  
CTSC#  
2
XR16M564/564D  
REV. 1.0.0  
IGURE 3. PIN  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
F
O
UT  
A
SSIGNMENT  
F
OR 48-PIN QFN PACKAGE AND 80-PIN LQFP PACKAGE  
RXD  
36  
35  
34  
33  
CTSA#  
VCC  
1
2
CTSD#  
GND  
RTSA#  
INTA  
CSA#  
TXA  
3
4
5
6
7
8
9
RTSD#  
32 INTD  
CSD#  
XR16M564  
48-pin QFN  
31  
IOW#  
TXB  
30 TXD  
29 IOR#  
CSB#  
28  
27  
26  
25  
TXC  
INTB  
RTSB#  
CTSB#  
CSC#  
INTC  
10  
11  
12  
RTSC#  
NC  
1
2
3
60  
59  
58  
57  
56  
NC  
CDD#  
CDC#  
RIC#  
RID#  
RXD  
RXC  
GND  
4
5
6
7
8
VCC  
INTSEL  
55 TXRDY#  
RXRDY#  
D0  
D1  
54  
53  
52  
51  
RESET  
NC  
XR16M 564  
D2  
9
-
80 pin LQFP  
XTAL2  
NC  
10  
Intel Mode Only  
50 XTAL1  
D3  
11  
12  
49  
NC  
A0  
D4  
D5  
13  
48  
47  
46  
A1  
A2  
14  
15  
D6  
D7  
16  
17  
18  
19  
20  
GND  
RXA  
45  
44  
43  
42  
41  
VCC  
RXB  
RIA#  
CDA#  
NC  
RIB#  
CDB#  
NC  
3
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
ORDERING INFORMATION  
REV. 1.0.0  
O
PERATING  
T
EMPERATURE  
PART  
N
UMBER  
P
ACKAGE  
DEVICE STATUS  
RANGE  
XR16M564IJ68  
XR16M564IV64  
68-Lead PLCC  
64-Lead LQFP  
-40°C to +85°C  
-40°C to +85°C  
Active  
Active  
XR16M564DIV64  
XR16M564IL48  
XR16M564IV80  
64-Lead LQFP  
48-pin QFN  
-40°C to +85°C  
-40°C to +85°C  
-40°C to +85°C  
Active  
Active  
Active  
80-Lead LQFP  
PIN DESCRIPTIONS  
Pin Description  
48-QFN 64-LQFP 68-PLCC 80-LQFP  
NAME  
TYPE  
DESCRIPTION  
P
IN  
#
P
IN  
#
P
IN  
#
PIN #  
DATA BUS INTERFACE  
A2  
A1  
A0  
15  
16  
17  
22  
23  
24  
32  
33  
34  
46  
47  
48  
I
Address data lines [2:0]. These 3 address lines select  
one of the internal registers in UART channel A-D dur-  
ing a data bus transaction.  
D7  
D6  
D5  
D4  
D3  
D2  
D1  
D0  
46  
45  
44  
43  
42  
41  
40  
39  
60  
59  
58  
57  
56  
55  
54  
53  
5
4
15  
14  
13  
12  
11  
9
I/O Data bus lines [7:0] (bidirectional).  
3
2
1
68  
67  
66  
8
7
IOR#  
29  
40  
52  
70  
I
When 16/68# pin is HIGH, the Intel bus interface is  
selected and this input becomes read strobe (active  
low). The falling edge instigates an internal read cycle  
and retrieves the data byte from an internal register  
pointed by the address lines [A2:A0], puts the data  
byte on the data bus to allow the host processor to  
read it on the rising edge.  
(VCC)  
When 16/68# pin is LOW, the Motorola bus interface is  
selected and this input is not used and should be con-  
nected to VCC.  
IOW#  
7
9
18  
31  
I
When 16/68# pin is HIGH, it selects Intel bus interface  
and this input becomes write strobe (active low). The  
falling edge instigates the internal write cycle and the  
rising edge transfers the data byte on the data bus to  
an internal register pointed by the address lines.  
(R/W#)  
When 16/68# pin is LOW, the Motorola bus interface is  
selected and this input becomes read (logic 1) and  
write (LOW) signal.  
CSA#  
(CS#)  
5
7
16  
28  
I
When 16/68# pin is HIGH, this input is chip select A  
(active low) to enable channel A in the device.  
When 16/68# pin is LOW, this input becomes the chip  
select (active low) for the Motorola bus interface.  
4
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
Pin Description  
48-QFN 64-LQFP 68-PLCC 80-LQFP  
NAME  
TYPE  
DESCRIPTION  
P
IN  
#
P
IN  
#
P
IN  
#
PIN #  
CSB#  
(A3)  
9
11  
20  
33  
I
I
I
When 16/68# pin is HIGH, this input is chip select B  
(active low) to enable channel B in the device.  
When 16/68# pin is LOW, this input becomes address  
line A3 which is used for channel selection in the  
Motorola bus interface.  
CSC#  
(A4)  
27  
38  
50  
68  
When 16/68# pin is HIGH, this input is chip select C  
(active low) to enable channel C in the device.  
When 16/68# pin is LOW, this input becomes address  
line A4 which is used for channel selection in the  
Motorola bus interface.  
CSD#  
(VCC)  
31  
4
42  
6
54  
15  
73  
27  
When 16/68# pin is HIGH, this input is chip select D  
(active low) to enable channel D in the device.  
When 16/68# pin is LOW, this input is not used and  
should be connected VCC.  
INTA  
O
When 16/68# pin is HIGH for Intel bus interface, this  
ouput becomes channel A interrupt output. The output  
state is defined by the user and through the software  
setting of MCR[3]. INTA is set to the active mode when  
MCR[3] is set to a logic 1. INTA is set to the three state  
mode when MCR[3] is set to a logic 0 (default). See  
MCR[3].  
(IRQ#)  
(OD)  
When 16/68# pin is LOW for Motorola bus interface,  
this output becomes device interrupt output (active  
low, open drain). An external pull-up resistor is  
required for proper operation.  
INTB  
INTC  
INTD  
(N.C.)  
10  
26  
32  
12  
37  
43  
21  
49  
55  
34  
67  
74  
O
When 16/68# pin is HIGH for Intel bus interface, these  
ouputs become the interrupt outputs for channels B, C,  
and D. The output state is defined by the user through  
the software setting of MCR[3]. The interrupt outputs  
are set to the active mode when MCR[3] is set to a  
logic 1 and are set to the three state mode when  
MCR[3] is set to a logic 0 (default). See MCR[3].  
When 16/68# pin is LOW for Motorola bus interface,  
these outputs are unused and will stay at logic zero  
level. Leave these outputs unconnected.  
TXRDY#  
RXRDY#  
-
-
-
-
39  
38  
55  
54  
O
O
Transmitter Ready (active low). This output is a logi-  
cally ANDed status of TXRDY# A-D. See Table 5. If  
this output is unused, leave it unconnected.  
Receiver Ready (active low). This output is a logically  
ANDed status of RXRDY# A-D. See Table 5. If this  
output is unused, leave it unconnected.  
5
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
Pin Description  
REV. 1.0.0  
48-QFN 64-LQFP 68-PLCC 80-LQFP  
NAME  
TYPE  
DESCRIPTION  
P
IN  
#
P
IN  
#
P
IN  
#
P
IN  
#
INTSEL  
38  
-
65  
6
I
Interrupt Select (active high, input with internal pull-  
down).  
When 16/68# pin is HIGH for Intel bus interface, this  
pin can be used in conjunction with MCR bit-3 to  
enable or disable the INT A-D pins or override MCR  
bit-3 and enable the interrupt outputs. Interrupt out-  
puts are enabled continuously when this pin is HIGH.  
MCR bit-3 enables and disables the interrupt output  
pins. In this mode, MCR bit-3 is set to a logic 1 to  
enable the continuous output. See MCR bit-3 descrip-  
tion for full detail. This pin must be LOW in the Motor-  
ola bus interface mode. For the 64 pin packages, this  
pin is bonded to VCC internally in the XR16M564D so  
the INT outputs operate in the continuous interrupt  
mode. This pin is bonded to GND internally in the  
XR16M564 and therefore requires setting MCR bit-3  
for enabling the interrupt output pins.  
MODEM OR SERIAL I/O INTERFACE  
TXA  
TXB  
TXC  
TXD  
6
8
8
17  
19  
51  
53  
29  
32  
69  
72  
O
UART channels A-D Transmit Data and infrared trans-  
mit data. Standard transmit and receive interface is  
enabled when MCR[6] = 0. In this mode, the TX signal  
will be a HIGH during reset, or idle (no data). Infrared  
IrDA transmit and receive interface is enabled when  
MCR[6] = 1. In the Infrared mode, the inactive state  
(no data) for the Infrared encoder/decoder interface is  
a logic 0.  
10  
39  
41  
28  
30  
RXA  
RXB  
RXC  
RXD  
48  
13  
22  
36  
62  
20  
29  
51  
7
17  
44  
57  
4
I
UART channel A-D Receive Data or infrared receive  
data. Normal receive data input must idle HIGH.  
29  
41  
63  
RTSA#  
RTSB#  
RTSC#  
RTSD#  
3
5
14  
22  
48  
56  
26  
35  
66  
75  
O
UART channels A-D Request-to-Send (active low) or  
general purpose output. This output must be asserted  
prior to using auto RTS flow control, see EFR[6],  
MCR[1], and IER[6]. Also see Figure 11. If these  
outputs are not used, leave them unconnected.  
11  
25  
33  
13  
36  
44  
CTSA#  
CTSB#  
CTSC#  
CTSD#  
1
2
11  
25  
45  
59  
23  
38  
63  
78  
I
UART channels A-D Clear-to-Send (active low) or gen-  
eral purpose input. It can be used for auto CTS flow  
12  
23  
35  
16  
33  
47  
control, see EFR[7], and IER[7]. Also see Figure 11  
These inputs should be connected to VCC when not  
used.  
.
DTRA#  
DTRB#  
DTRC#  
DTRD#  
-
-
-
-
3
12  
24  
46  
58  
24  
37  
64  
77  
O
I
UART channels A-D Data-Terminal-Ready (active low)  
or general purpose output. If these outputs are not  
used, leave them unconnected.  
15  
34  
46  
DSRA#  
DSRB#  
DSRC#  
DSRD#  
-
-
-
-
1
10  
26  
44  
60  
22  
39  
62  
79  
UART channels A-D Data-Set-Ready (active low) or  
general purpose input. This input should be connected  
to VCC when not used. This input has no effect on the  
UART.  
17  
32  
48  
6
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
Pin Description  
48-QFN 64-LQFP 68-PLCC 80-LQFP  
NAME  
TYPE  
DESCRIPTION  
P
IN  
#
P
IN  
#
P
IN  
#
PIN #  
CDA#  
CDB#  
CDC#  
CDD#  
-
-
-
-
64  
18  
31  
49  
9
19  
42  
59  
2
I
UART channels A-D Carrier-Detect (active low) or  
general purpose input. This input should be connected  
to VCC when not used. This input has no effect on the  
UART.  
27  
43  
61  
RIA#  
RIB#  
RIC#  
RID#  
-
-
-
-
63  
19  
30  
50  
8
18  
43  
58  
3
I
UART channels A-D Ring-Indicator (active low) or gen-  
eral purpose input. This input should be connected to  
VCC when not used. This input has no effect on the  
UART.  
28  
42  
62  
ANCILLARY SIGNALS  
XTAL1  
XTAL2  
16/68#  
18  
19  
14  
25  
26  
-
35  
36  
31  
50  
51  
-
I
O
I
Crystal or external clock input.  
Crystal or buffered clock output.  
Intel or Motorola Bus Select (input with internal pull-  
up).  
When 16/68# pin is HIGH, 16 or Intel Mode, the device  
will operate in the Intel bus type of interface.  
When 16/68# pin is LOW, 68 or Motorola mode, the  
device will operate in the Motorola bus type of inter-  
face.  
Motorola bus interface is not available on the 64 pin  
package.  
CLKSEL  
-
21  
27  
30  
37  
-
I
I
Baud-Rate-Generator Input Clock Prescaler Select for  
channels A-D. This input is only sampled during power  
up or a reset. Connect to VCC for divide by 1 (default)  
and GND for divide by 4. MCR[7] can override the  
state of this pin following a reset or initialization. See  
MCR bit-7 and Figure 6 in the Baud Rate Generator  
section.  
RESET  
20  
53  
When 16/68# pin is HIGH for Intel bus interface, this  
input becomes the Reset pin (active high). In this  
case, a 40 ns minimum HIGH pulse on this pin will  
reset the internal registers and all outputs. The UART  
transmitter output will be held HIGH, the receiver input  
will be ignored and outputs are reset during reset  
period (Table 17). When 16/68# pin is at LOW for  
Motorola bus interface, this input becomes Reset# pin  
(active low). This pin functions similarly, but instead of  
a HIGH pulse, a 40 ns minimum LOW pulse will reset  
the internal registers and outputs.  
(RESET#)  
Motorola bus interface is not available on the 64 pin  
package.  
VCC  
GND  
2, 24, 37 4, 35, 52  
13, 47, 5, 25, 45, Pwr 1.62V to 3.63V power supply.  
64  
65  
21, 47  
14, 28, 6, 23, 40,  
16, 36,  
56, 76  
Pwr Power supply common, ground.  
45, 61 57  
7
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
Pin Description  
REV. 1.0.0  
48-QFN 64-LQFP 68-PLCC 80-LQFP  
NAME  
TYPE  
DESCRIPTION  
P
IN  
#
P
IN  
#
P
IN  
#
PIN #  
GND  
Center  
Pad  
N/A  
N/A  
N/A  
Pwr  
The center pad on the backside of the QFN package is  
metallic and should be connected to GND on the PCB.  
The thermal pad size on the PCB should be the  
approximate size of this center pad and should be sol-  
der mask defined. The solder mask opening should be  
at least 0.0025" inwards from the edge of the PCB  
thermal pad.  
N.C.  
-
-
-
1, 10, 20,  
21, 30,  
40, 41,  
49, 52,  
60, 61,  
71, 80  
No Connection. These pins are not used in either the  
Intel or Motorola bus modes.  
Pin type: I=Input, O=Output, I/O= Input/Output, OD=Output Open Drain.  
8
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
1.0 PRODUCT DESCRIPTION  
The XR16M564 (M564) integrates the functions of 4 enhanced 16C550 Universal Asynchrounous Receiver  
and Transmitter (UART). Each UART is independently controlled and has its own set of device configuration  
registers. The configuration registers set is 16550 UART compatible for control, status and data transfer.  
Additionally, each UART channel has 32 bytes of transmit and receive FIFOs, automatic RTS/CTS hardware  
flow control, automatic Xon/Xoff and special character software flow control, infrared encoder and decoder  
(IrDA ver 1.0), programmable fractional baud rate generator with a prescaler of dividing by 1 or 4, and data rate  
up to 16 Mbps. The XR16M564 can operate from 1.62 to 3.63 volts. The M564 is fabricated with an advanced  
CMOS process.  
Enhanced FIFO  
The M564 QUART provides a solution that supports 32 bytes of transmit and receive FIFO memory, instead of  
16 bytes in the ST16C554, or one byte in the ST16C454. The M564 is designed to work with high performance  
data communication systems, that require fast data processing time. Increased performance is realized in the  
M564 by the larger transmit and receive FIFOs, FIFO trigger level control and automatic flow control  
mechanism. This allows the external processor to handle more networking tasks within a given time. For  
example, the ST16C554 with a 16 byte FIFO, unloads 16 bytes of receive data in 1.53 ms (This example uses  
a character length of 11 bits, including start/stop bits at 115.2Kbps). This means the external CPU will have to  
service the receive FIFO at 1.53 ms intervals. However with the 32 byte FIFO in the M564, the data buffer will  
not require unloading/loading for 3.1 ms. This increases the service interval giving the external CPU additional  
time for other applications and reducing the overall UART interrupt servicing time. In addition, the  
programmable FIFO level trigger interrupt and automatic hardware/software flow control is uniquely provided  
for maximum data throughput performance especially when operating in a multi-channel system. The  
combination of the above greatly reduces the CPU’s bandwidth requirement, increases performance, and  
reduces power consumption.  
Data Rate  
The M564 is capable of operation up to 16 Mbps at 3.3V with 4Xinternal sampling clock rate. The device can  
operate at 3.3V with a crystal oscillator of up to 24 MHz crystal on pins XTAL1 and XTAL2, or external clock  
source of 64 MHz on XTAL1 pin. With a typical crystal of 14.7456 MHz and through a software option, the user  
can set the prescaler bit and sampling rate for data rates of up to 3.68 Mbps.  
Enhanced Features  
The rich feature set of the M564 is available through the internal registers. Automatic hardware/software flow  
control, selectable transmit and receive FIFO trigger levels, selectable baud rates, infrared encoder/decoder  
interface, modem interface controls, and a sleep mode are all standard features. MCR bit-5 provides a facility  
for turning off (Xon) software flow control with any incoming (RX) character. In the 16 mode INTSEL and MCR  
bit-3 can be configured to provide a software controlled or continuous interrupt capability. For backward  
compatibility to the ST16C654, the 64-pin LQFP does not have the INTSEL pin. Instead, two different LQFP  
packages are offered. The XR16M564DIV operates in the continuous interrupt enable mode by internally  
bonding INTSEL to VCC. The XR16M564IV operates in conjunction with MCR bit-3 by internally bonding  
INTSEL to GND.  
The XR16M564 offers a clock prescaler select pin to allow system/board designers to preset the default baud  
rate table on power up. The CLKSEL pin selects the div-by-1 or div-by-4 prescaler for the baud rate generator.  
It can then be overridden following initialization by MCR bit-7.  
9
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.0 FUNCTIONAL DESCRIPTIONS  
REV. 1.0.0  
2.1  
CPU Interface  
The CPU interface is 8 data bits wide with 3 address lines and control signals to execute data bus read and  
write transactions. The M564 data interface supports the Intel compatible types of CPUs and it is compatible to  
the industry standard 16C550 UART. No clock (oscillator nor external clock) is required for a data bus  
transaction. Each bus cycle is asynchronous using CS# A-D, IOR# and IOW# or CS#, R/W#, A4 and A3 inputs.  
All four UART channels share the same data bus for host operations. A typical data bus interconnection for  
Intel and Motorola mode is shown in Figure 4.  
F
IGURE 4. XR16M564 TYPICAL  
INTEL/MOTOROLA  
DATA  
B
US  
I
NTERCONNECTIONS  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
VCC  
VCC  
TXA  
RXA  
DTRA#  
RTSA#  
UART  
Serial Interface of  
CTSA#  
DSRA#  
CDA#  
RIA#  
Channel A  
RS-232  
A0  
A1  
A2  
A0  
A1  
A2  
IOR#  
IOR#  
IOW#  
UART  
IOW#  
Channel B  
Similar  
CSA#  
CSB#  
CSC#  
CSD#  
UART_CSA#  
UART_CSB#  
UART_CSC#  
UART_CSD#  
to Ch A  
UART  
Channel C  
Serial Interface of  
RS-232  
Similar  
to Ch A  
UART_INTA  
UART_INTB  
UART_INTC  
UART_INTD  
INTA  
INTB  
INTC  
INTD  
UART  
Channel D  
Similar  
to Ch A  
UART_RESET  
VCC  
RESET  
16/68#  
GND  
Intel Data Bus (16 Mode) Interconnections  
VCC  
VCC  
D0  
D1  
D2  
D3  
D4  
D5  
D6  
D7  
D0  
D1  
D2  
D3  
D4  
D5  
TXA  
RXA  
DTRA#  
RTSA#  
CTSA#  
DSRA#  
CDA#  
RIA#  
D6  
UART  
Channel A  
Serial Interface of  
RS-232  
D7  
A0  
A1  
A0  
A1  
A2  
A2  
A3  
A4  
CSB#  
CSC#  
CSD#  
UART  
Channel B  
VCC  
VCC  
Similar  
to Ch A  
IOR#  
IOW#  
R/W#  
UART  
Channel C  
CSA#  
UART_CS#  
Similar  
to Ch A  
Serial Interface of  
RS-232  
VCC  
UART_IRQ#  
INTA  
UART  
Channel D  
INTB  
INTC  
INTD  
(no connect)  
(no connect)  
(no connect)  
Similar  
to Ch A  
UART_RESET#  
RESET#  
16/68#  
GND  
Motorola Data Bus (68 Mode) Interconnections  
10  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.2  
Device Reset  
The RESET input resets the internal registers and the serial interface outputs in both channels to their default  
state (see Table 17). An active high pulse of longer than 40 ns duration will be required to activate the reset  
function in the device. Following a power-on reset or an external reset, the M564 is software compatible with  
previous generation of UARTs, 16C454 and 16C554.  
2.3  
Channel Selection  
The UART provides the user with the capability to bi-directionally transfer information between an external  
CPU and an external serial communication device. During Intel Bus Mode (16/68# pin is connected to VCC), a  
LOW on chip select pins, CSA#, CSB#, CSC# or CSD# allows the user to select UART channel A, B, C or D to  
configure, send transmit data and/or unload receive data to/from the UART. Selecting all four UARTs can be  
useful during power up initialization to write to the same internal registers, but do not attempt to read from all  
four uarts simultaneously. Individual channel select functions are shown in Table 1.  
TABLE 1: CHANNEL A-D SELECT IN 16 MODE  
CSA# CSB# CSC# CSD#  
FUNCTION  
1
0
1
1
1
0
1
1
0
1
1
0
1
1
1
0
1
0
1
1
1
1
0
0
UART de-selected  
Channel A selected  
Channel B selected  
Channel C selected  
Channel D selected  
Channels A-D selected  
During Motorola Bus Mode (16/68# pin is connected to GND), the package interface pins are configured for  
connection with Motorola, and other popular microprocessor bus types. In this mode the M564 decodes two  
additional addresses, A3 and A4, to select one of the four UART ports. The A3 and A4 address decode  
function is used only when in the Motorola Bus Mode. See Table 2.  
TABLE 2: CHANNEL A-D SELECT IN 68 MODE  
CS#  
A4  
A3  
X
0
FUNCTION  
1
0
0
0
0
X
0
0
1
1
UART de-selected  
Channel A selected  
Channel B selected  
Channel C selected  
Channel D selected  
1
0
1
11  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
2.4  
Channels A-D Internal Registers  
Each UART channel in the M564 has a set of enhanced registers for controlling, monitoring and data loading  
and unloading. The configuration register set is compatible to those already available in the standard single  
16C550. These registers function as data holding registers (THR/RHR), interrupt status and control registers  
(ISR/IER), a FIFO control register (FCR), receive line status and control registers (LSR/LCR), modem status  
and control registers (MSR/MCR), programmable data rate (clock) divisor registers (DLL/DLM/DLD), and a  
user accessible scratchpad register (SPR).  
Beyond the general 16C550 features and capabilities, the M564 offers enhanced feature registers (EFR, Xon/  
Xoff 1, Xon/Xoff 2) that provide automatic RTS and CTS hardware flow control and automatic Xon/Xoff  
software flow control. All the register functions are discussed in full detail later in “Section 3.0, UART  
INTERNAL REGISTERS” on page 24.  
2.5  
INT Ouputs for Channels A-D  
The interrupt outputs change according to the operating mode and enhanced features setup. Table 3 and 4  
summarize the operating behavior for the transmitter and receiver. Also see Figure 20 through 25.  
TABLE 3: INT PIN  
O
PERATION FOR  
TRANSMITTER FOR  
CHANNELS A-D  
FCR BIT-0 = 1 (FIFO ENABLED  
)
FCR BIT-0 = 0  
FCR Bit-3 = 0  
(DMA Mode Disabled)  
FCR Bit-3 = 1  
(FIFO DISABLED  
)
(DMA Mode Enabled)  
INT Pin  
LOW = a byte in THR  
HIGH = THR empty  
LOW = FIFO above trigger level  
LOW = FIFO above trigger level  
HIGH = FIFO below trigger level or  
FIFO empty  
HIGH = FIFO below trigger level or  
FIFO empty  
TABLE 4: INT PIN  
O
PERATION FOR  
R
ECEIVER FOR  
C
HANNELS A-D  
FCR BIT-0 = 0  
FCR BIT-0 = 1 (FIFO ENABLED  
)
(FIFO DISABLED  
)
FCR Bit-3 = 0  
FCR Bit-3 = 1  
(DMA Mode Disabled)  
(DMA Mode Enabled)  
INT Pin  
LOW = no data  
HIGH = 1 byte  
LOW = FIFO below trigger level  
HIGH = FIFO above trigger level  
LOW = FIFO below trigger level  
HIGH = FIFO above trigger level  
2.6  
DMA Mode  
The device does not support direct memory access. The DMA Mode (a legacy term) in this document does not  
mean “direct memory access” but refers to data block transfer operation. The DMA mode affects the state of  
the RXRDY# A-D and TXRDY# A-D output pins. The transmit and receive FIFO trigger levels provide  
additional flexibility to the user for block mode operation. The LSR bits 5-6 provide an indication when the  
transmitter is empty or has an empty location(s) for more data. The user can optionally operate the transmit  
and receive FIFO in the DMA mode (FCR bit-3 = 1). When the transmit and receive FIFOs are enabled and the  
DMA mode is disabled (FCR bit-3 = 0), the M564 is placed in single-character mode for data transmit or  
receive operation. When DMA mode is enabled (FCR bit-3 = 1), the user takes advantage of block mode  
12  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
operation by loading or unloading the FIFO in a block sequence determined by the programmed trigger level.  
The following table show their behavior. Also see Figure 20 through 25.  
TABLE 5: TXRDY# AND RXRDY# OUTPUTS IN FIFO AND DMA MODE FOR CHANNELS A-D  
FCR BIT-0=0  
P
INS  
FCR BIT-0=1 (FIFO ENABLED)  
(FIFO DISABLED  
)
FCR BIT-3 = 0  
(DMA MODE  
FCR BIT-3 = 1  
(DMA MODE ENABLED)  
D
ISABLED  
)
RXRDY#  
TXRDY#  
LOW = 1 byte  
LOW = at least 1 byte in FIFO  
HIGH = FIFO empty  
HIGH to LOW transition when FIFO reaches the  
trigger level, or timeout occurs  
HIGH = no data  
LOW to HIGH transition when FIFO empties  
LOW = THR empty  
LOW = FIFO empty  
LOW = FIFO has at least 1 empty location  
HIGH = FIFO is full  
HIGH = byte in THR HIGH = at least 1 byte in FIFO  
2.7  
Crystal Oscillator or External Clock Input  
The M564 includes an on-chip oscillator (XTAL1 and XTAL2) to produce a clock for both UART sections in the  
device. The CPU data bus does not require this clock for bus operation. The crystal oscillator provides a  
system clock to the Baud Rate Generators (BRG) section found in each of the UART. XTAL1 is the input to the  
oscillator or external clock buffer input with XTAL2 pin being the output. For programming details, see  
“Section 2.8, Programmable Baud Rate Generator with Fractional Divisor” on page 13.  
F
IGURE 5. TYPICAL CRYSTAL CONNECTIONS  
R=300K to 400K  
14.7456  
MHz  
XTAL2  
XTAL1  
C1  
C2  
22-47pF  
22-47pF  
The on-chip oscillator is designed to use an industry standard microprocessor crystal (parallel resonant,  
fundamental frequency with 10-22 pF capacitance load, ESR of 20-120 ohms and 100ppm frequency  
tolerance) connected externally between the XTAL1 and XTAL2 pins. Typical oscillator connections are shown  
in Figure 5. Alternatively, an external clock can be connected to the XTAL1 pin to clock the internal baud rate  
generator for standard or custom rates. For further reading on oscillator circuit please see application note  
DAN108 on EXAR’s web site.  
2.8  
Programmable Baud Rate Generator with Fractional Divisor  
Each UART has its own Baud Rate Generator (BRG) with a prescaler for the transmitter and receiver. The  
prescaler is controlled by a software bit in the MCR register. The MCR register bit-7 sets the prescaler to divide  
the input crystal or external clock by 1 or 4. The output of the prescaler clocks to the BRG. The BRG further  
16  
divides this clock by a programmable divisor between 1 and (2 - 0.0625) in increments of 0.0625 (1/16) to  
obtain a 16X or 8X or 4X sampling clock of the serial data rate. The sampling clock is used by the transmitter  
for data bit shifting and receiver for data sampling. The BRG divisor (DLL, DLM and DLD registers) defaults to  
the value of ’1’ (DLL = 0x01, DLM = 0x00 and DLD = 0x00) upon reset. Therefore, the BRG must be  
13  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
programmed during initialization to the operating data rate. The DLL and DLM registers provide the integer part  
of the divisor and the DLD register provides the fractional part of the divisor. Only the four lower bits of the DLD  
are implemented and they are used to select a value from 0 (for setting 0000) to 0.9375 or 15/16 (for setting  
1111). Programming the Baud Rate Generator Registers DLL, DLM and DLD provides the capability for  
selecting the operating data rate. Table 6 shows the standard data rates available with a 24MHz crystal or  
external clock at 16X clock rate. If the pre-scaler is used (MCR bit-7 = 1), the output data rate will be 4 times  
less than that shown in Table 6. At 8X sampling rate, these data rates would double. And at 4X sampling rate,  
they would quadruple. Also, when using 8X sampling mode, please note that the bit-time will have a jitter (+/- 1/  
16) whenever the DLD is non-zero and is an odd number. When using a non-standard data rate crystal or  
external clock, the divisor value can be calculated with the following equation(s):  
Required Divisor (decimal)=(XTAL1 clock frequency / prescaler) /(serial data rate x 16), with 16X mode, DLD[5:4]=’00’  
Required Divisor (decimal)= (XTAL1 clock frequency / prescaler / (serial data rate x 8), with 8X mode, DLD[5:4] = ’01’  
Required Divisor (decimal)= (XTAL1 clock frequency / prescaler / (serial data rate x 4), with 4X mode, DLD[5:4] = ’10’  
The closest divisor that is obtainable in the M564 can be calculated using the following formula:  
ROUND( (Required Divisor - TRUNC(Required Divisor) )*16)/16 + TRUNC(Required Divisor), where  
DLM = TRUNC(Required Divisor) >> 8  
DLL = TRUNC(Required Divisor) & 0xFF  
DLD = ROUND( (Required Divisor-TRUNC(Required Divisor) )*16)  
In the formulas above, please note that:  
TRUNC (N) = Integer Part of N. For example, TRUNC (5.6) = 5.  
ROUND (N) = N rounded towards the closest integer. For example, ROUND (7.3) = 7 and ROUND (9.9) = 10.  
A >> B indicates right shifting the value ’A’ by ’B’ number of bits. For example, 0x78A3 >> 8 = 0x0078.  
FIGURE 6. BAUD  
R
ATE  
G
ENERATOR  
To Other  
Channels  
DLL, DLM and DLD  
Registers  
MCR Bit-7=0  
(default)  
Prescaler  
Divide by 1  
16X or 8X or 4X  
Sampling  
Rate Clock  
to Transmitter  
and Receiver  
Crystal  
Osc/  
Buffer  
XTAL1  
XTAL2  
Fractional Baud  
Rate Generator  
Logic  
Prescaler  
Divide by 4  
MCR Bit-7=1  
14  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
TABLE 6: TYPICAL DATA RATES WITH A 24 MHZ CRYSTAL OR EXTERNAL CLOCK AT 16X SAMPLING  
Required  
Output Data  
Rate  
D
IVISOR FOR 16x  
Clock  
(Decimal)  
DIVISOR  
BTAINABLE IN  
DLM PROGRAM DLL PROGRAM DLD PROGRAM  
ALUE (HEX) ALUE (HEX) ALUE (HEX)  
DATA ERROR  
O
V
V
V
RATE (%)  
V2550  
400  
2400  
3750  
625  
3750  
625  
E
2
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
A6  
71  
38  
9C  
96  
4E  
3C  
34  
27  
1E  
1A  
14  
F
0
0
8
4
0
2
0
1
1
0
1
0
0
0
C
8
B
8
0
0
C
4
0
0
A
8
0
0
4800  
312.5  
156.25  
150  
312 8/16  
156 4/16  
150  
0
9600  
0
10000  
19200  
25000  
28800  
38400  
50000  
57600  
75000  
100000  
115200  
153600  
200000  
225000  
230400  
250000  
300000  
400000  
460800  
500000  
750000  
921600  
1000000  
0
78.125  
60  
78 2/16  
60  
0
0
52.0833  
39.0625  
30  
52 1/16  
39 1/16  
30  
0.04  
0
0
26.0417  
20  
26 1/16  
20  
0.08  
0
15  
15  
0
13.0208  
9.7656  
7.5  
13  
D
0.16  
0.16  
0
9 12/16  
7 8/16  
6 11/16  
6 8/16  
6
9
7
6.6667  
6.5104  
6
6
0.31  
0.16  
0
6
6
5
5
5
0
3.75  
3 12/16  
3 4/16  
3
3
0
3.2552  
3
3
0.16  
0
3
2
2
2
0
1.6276  
1.5  
1 10/16  
1 8/16  
1
0.16  
0
1
2.9  
Transmitter  
The transmitter section comprises of an 8-bit Transmit Shift Register (TSR) and 32 bytes of FIFO which  
includes a byte-wide Transmit Holding Register (THR). TSR shifts out every data bit with the 16X/8X/4X  
internal clock. A bit time is 16/8/4 clock periods. The transmitter sends the start-bit followed by the number of  
data bits, inserts the proper parity-bit if enabled, and adds the stop-bit(s). The status of the FIFO and TSR are  
reported in the Line Status Register (LSR bit-5 and bit-6).  
2.9.1  
Transmit Holding Register (THR) - Write Only  
The transmit holding register is an 8-bit register providing a data interface to the host processor. The host  
writes transmit data byte to the THR to be converted into a serial data stream including start-bit, data bits,  
parity-bit and stop-bit(s). The least-significant-bit (Bit-0) becomes first data bit to go out. The THR is the input  
register to the transmit FIFO of 32 bytes when FIFO operation is enabled by FCR bit-0. Every time a write  
operation is made to the THR, the FIFO data pointer is automatically bumped to the next sequential data  
location.  
15  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
2.9.2  
Transmitter Operation in non-FIFO Mode  
The host loads transmit data to THR one character at a time. The THR empty flag (LSR bit-5) is set when the  
data byte is transferred to TSR. THR flag can generate a transmit empty interrupt (ISR bit-1) when it is enabled  
by IER bit-1. The TSR flag (LSR bit-6) is set when TSR becomes completely empty.  
F
IGURE 7. TRANSMITTER OPERATION IN NON-FIFO MODE  
Data  
Byte  
Transmit  
Holding  
Register  
(THR)  
THR Interrupt (ISR bit-1)  
Enabled by IER bit-1  
16X or 8X or 4X  
Clock  
( DLD[5:4] )  
M
S
B
L
S
B
Transmit Shift Register (TSR)  
TXNOFIFO1  
2.9.3  
Transmitter Operation in FIFO Mode  
The host may fill the transmit FIFO with up to 32 bytes of transmit data. The THR empty flag (LSR bit-5) is set  
whenever the FIFO is empty. The THR empty flag can generate a transmit empty interrupt (ISR bit-1) when the  
FIFO becomes empty. The transmit empty interrupt is enabled by IER bit-1. The TSR flag (LSR bit-6) is set  
when TSR/FIFO becomes empty.  
F
IGURE 8. TRANSMITTER  
O
PERATION IN FIFO AND  
F
LOW  
C
ONTROL  
M
ODE  
Transmit  
FIFO  
Transmit  
Data Byte  
THR Interrupt (ISR bit-1) falls  
below the programmed Trigger  
Level and then when becomes  
empty. FIFO is Enabled by FCR  
bit-0=1  
Auto CTS Flow Control (CTS# pin)  
Flow Control Characters  
(Xoff1/2 and Xon1/2 Reg.)  
Auto Software Flow Control  
16X or 8X or 4X Clock  
(DLD[5:4])  
Transmit Data Shift Register  
(TSR)  
TXFIFO1  
16  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.10 Receiver  
The receiver section contains an 8-bit Receive Shift Register (RSR) and 32 bytes of FIFO which includes a  
byte-wide Receive Holding Register (RHR). The RSR uses the 16X/8X/4X clock (DLD[5:4]) for timing. It  
verifies and validates every bit on the incoming character in the middle of each data bit. On the falling edge of  
a start or false start bit, an internal receiver counter starts counting at the 16X/8X/4X clock rate. After 8 clocks  
(or 4 if 8X or 2 if 4X) the start bit period should be at the center of the start bit. At this time the start bit is  
sampled and if it is still LOW it is validated. Evaluating the start bit in this manner prevents the receiver from  
assembling a false character. The rest of the data bits and stop bits are sampled and validated in this same  
manner to prevent false framing. If there were any error(s), they are reported in the LSR register bits 2-4. Upon  
unloading the receive data byte from RHR, the receive FIFO pointer is bumped and the error tags are  
immediately updated to reflect the status of the data byte in RHR register. RHR can generate a receive data  
ready interrupt upon receiving a character or delay until it reaches the FIFO trigger level. Furthermore, data  
delivery to the host is guaranteed by a receive data ready time-out interrupt when data is not received for 4  
word lengths as defined by LCR[1:0] plus 12 bits time. This is equivalent to 3.7-4.6 character times. The RHR  
interrupt is enabled by IER bit-0. See Figure 9 and Figure 10 below.  
2.10.1 Receive Holding Register (RHR) - Read-Only  
The Receive Holding Register is an 8-bit register that holds a receive data byte from the Receive Shift  
Register. It provides the receive data interface to the host processor. The RHR register is part of the receive  
FIFO of 32 bytes by 11-bits wide, the 3 extra bits are for the 3 error tags to be reported in LSR register. When  
the FIFO is enabled by FCR bit-0, the RHR contains the first data character received by the FIFO. After the  
RHR is read, the next character byte is loaded into the RHR and the errors associated with the current data  
byte are immediately updated in the LSR bits 2-4.  
F
IGURE 9. RECEIVER OPERATION IN NON-FIFO MODE  
16X or 8X or 4X Clock  
( DLD[5:4] )  
Receive Data Shift  
Register (RSR)  
Data Bit  
Validation  
Receive Data Characters  
Error  
Receive  
Data Byte  
and Errors  
Receive Data  
Holding Register  
(RHR)  
Tags in  
LSR bits  
4:2  
RHR Interrupt (ISR bit-2)  
RXFIFO1  
17  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
F
IGURE 10. RECEIVER  
O
PERATION IN FIFO AND  
A
UTO RTS FLOW CONTROL MODE  
16X or 8X or 4X Clock  
( DLD[5:4] )  
Receive Data Shift  
Register (RSR)  
Data Bit  
Validation  
Receive Data Characters  
Example  
- RX FIFO trigger level selected at 16 bytes  
:
(See Note Below)  
32 bytes by 11-bit wide  
FIFO  
Data falls to  
8
RTS# re-asserts when data falls below the flow  
control trigger level to restart remote transmitter.  
Enable by EFR bit-6=1, MCR bit-1.  
Receive  
Data FIFO  
FIFO  
Trigger=16  
RHR Interrupt (ISR bit-2) programmed for  
desired FIFO trigger level.  
FIFO is Enabled by FCR bit-0=1  
Data fills to  
24  
RTS# de-asserts when data fills above the flow  
control trigger level to suspend remote transmitter.  
Enable by EFR bit-6=1, MCR bit-1.  
Receive  
Data  
Receive Data  
Byte and Errors  
RXFIFO1  
2.11 Auto RTS (Hardware) Flow Control  
Automatic RTS hardware flow control is used to prevent data overrun to the local receiver FIFO. The RTS#  
output is used to request remote unit to suspend/resume data transmission. The auto RTS flow control  
features is enabled to fit specific application requirement (see Figure 11):  
Enable auto RTS flow control using EFR bit-6.  
The auto RTS function must be started by asserting RTS# output pin (MCR bit-1 to logic 1 after it is enabled).  
If using the Auto RTS interrupt:  
Enable RTS interrupt through IER bit-6 (after setting EFR bit-4). The UART issues an interrupt when the RTS#  
pin makes a transition from low to high: ISR bit-5 will be set to logic 1.  
2.12 Auto RTS Hysteresis  
The M564 has a new feature that provides flow control trigger hysteresis while maintaining compatibility with  
the XR16C850, ST16C650A and ST16C550 family of UARTs. With the Auto RTS function enabled, an interrupt  
is generated when the receive FIFO reaches the selected RX trigger level. The RTS# pin will not be forced  
HIGH (RTS off) until the receive FIFO reaches one trigger level above the selected trigger level in the trigger  
table (Table 12). The RTS# pin will return LOW after the RX FIFO is unloaded to one level below the selected  
trigger level. Under the above described conditions, the M564 will continue to accept data until the receive  
FIFO gets full. The Auto RTS function is initiated when the RTS# output pin is asserted LOW (RTS On).  
TABLE 7: AUTO RTS (HARDWARE) FLOW  
CONTROL  
RTS# D  
E
-
ASSERTED (HIGH  
)
RTS# ASSERTED (LOW)  
R
X
TRIGGER  
LEVEL  
INT PIN ACTIVATION  
(CHARACTERS IN  
RX  
F
IFO  
)
(CHARACTERS IN RX FIFO)  
8
8
16  
24  
30  
30  
0
8
16  
24  
30  
16  
24  
30  
16  
24  
18  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.13 Auto CTS Flow Control  
Automatic CTS flow control is used to prevent data overrun to the remote receiver FIFO. The CTS# input is  
monitored to suspend/restart the local transmitter. The auto CTS flow control feature is selected to fit specific  
application requirement (see Figure 11):  
Enable auto CTS flow control using EFR bit-7.  
If needed, the CTS interrupt can be enabled through IER bit-7 (after setting EFR bit-4). The UART issues an  
interrupt when the CTS# pin is de-asserted (HIGH): ISR bit-5 will be set to 1, and UART will suspend  
transmission as soon as the stop bit of the character in process is shifted out. Transmission is resumed after  
the CTS# input is re-asserted (LOW), indicating more data may be sent.  
F
IGURE 11. AUTO RTS AND CTS FLOW CONTROL OPERATION  
Local UART  
UARTA  
Remote UART  
UARTB  
RXA  
TXB  
Receiver FIFO  
Trigger Reached  
Transmitter  
RTSA#  
TXA  
CTSB#  
RXB  
Auto RTS  
Auto CTS  
Monitor  
Trigger Level  
Receiver FIFO  
Trigger Reached  
Transmitter  
CTSA#  
RTSB#  
Auto CTS  
Monitor  
Auto RTS  
Trigger Level  
Assert RTS# to Begin  
Transmission  
1
10  
ON  
ON  
ON  
RTSA#  
OFF  
7
2
ON  
3
11  
OFF  
CTSB#  
TXB  
8
Restart  
9
Data Starts  
6
Suspend  
4
RXA FIFO  
Receive  
Data  
RX FIFO  
12  
RTS High  
Threshold  
RTS Low  
Threshold  
5
RX FIFO  
Trigger Level  
Trigger Level  
INTA  
(RXA FIFO  
Interrupt)  
RTSCTS1  
The local UART (UARTA) starts data transfer by asserting RTSA# (1). RTSA# is normally connected to CTSB# (2) of  
remote UART (UARTB). CTSB# allows its transmitter to send data (3). TXB data arrives and fills UARTA receive FIFO  
(4). When RXA data fills up to its receive FIFO trigger level, UARTA activates its RXA data ready interrupt (5) and con-  
tinues to receive and put data into its FIFO. If interrupt service latency is long and data is not being unloaded, UARTA  
monitors its receive data fill level to match the upper threshold of RTS delay and de-assert RTSA# (6). CTSB# follows  
(7) and request UARTB transmitter to suspend data transfer. UARTB stops or finishes sending the data bits in its trans-  
mit shift register (8). When receive FIFO data in UARTA is unloaded to match the lower threshold of RTS delay (9),  
UARTA re-asserts RTSA# (10), CTSB# recognizes the change (11) and restarts its transmitter and data flow again until  
next receive FIFO trigger (12). This same event applies to the reverse direction when UARTA sends data to UARTB  
with RTSB# and CTSA# controlling the data flow.  
19  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.14 Auto Xon/Xoff (Software) Flow Control  
REV. 1.0.0  
When software flow control is enabled (See Table 16), the M564 compares one or two sequential receive data  
characters with the programmed Xon or Xoff-1,2 character value(s). If receive character(s) (RX) match the  
programmed values, the M564 will halt transmission (TX) as soon as the current character has completed  
transmission. When a match occurs, the Xoff (if enabled via IER bit-5) flag will be set and the interrupt output  
pin will be activated. Following a suspension due to a match of the Xoff character, the M564 will monitor the  
receive data stream for a match to the Xon-1,2 character. If a match is found, the M564 will resume operation  
and clear the flags (ISR bit-4).  
Reset initially sets the contents of the Xon/Xoff 8-bit flow control registers to LOW. Following reset the user can  
write any Xon/Xoff value desired for software flow control. Different conditions can be set to detect Xon/Xoff  
characters (See Table 16) and suspend/resume transmissions. When double 8-bit Xon/Xoff characters are  
selected, the M564 compares two consecutive receive characters with two software flow control 8-bit values  
(Xon1, Xon2, Xoff1, Xoff2) and controls TX transmissions accordingly. Under the above described flow control  
mechanisms, flow control characters are not placed (stacked) in the user accessible RX data buffer or FIFO.  
In the event that the receive buffer is overfilling and flow control needs to be executed, the M564 automatically  
sends an Xoff message (when enabled) via the serial TX output to the remote modem. The M564 sends the  
Xoff-1,2 characters two-character-times (= time taken to send two characters at the programmed baud rate)  
after the receive FIFO crosses the programmed trigger level. To clear this condition, the M564 will transmit the  
programmed Xon-1,2 characters as soon as receive FIFO is less than one trigger level below the programmed  
trigger level. Table 8 below explains this.  
TABLE 8: AUTO  
X
ON/XOFF (SOFTWARE) FLOW  
C
ONTROL  
X
(
OFF  
C
HARACTER  
(
S
) SENT  
X
ON CHARACTER(S) SENT  
RX TRIGGER  
L
EVEL  
INT PIN  
ACTIVATION  
CHARACTERS IN RX FIFO  
)
(
CHARACTERS IN RX FIFO)  
8
8
8*  
0
8
16  
24  
30  
16  
24  
30  
16*  
24*  
30*  
16  
24  
* After the trigger level is reached, an xoff character is sent after a short span of time (= time required to send 2 characters);  
for example, after 2.083ms has elapsed for 9600 baud and 10-bit word length setting.  
2.15  
Special Character Detect  
A special character detect feature is provided to detect an 8-bit character when bit-5 is set in the Enhanced  
Feature Register (EFR). When this character (Xoff2) is detected, it will be placed in the FIFO along with normal  
incoming RX data.  
The M564 compares each incoming receive character with Xoff-2 data. If a match exists, the received data will  
be transferred to the RX FIFO and ISR bit-4 will be set to indicate detection of special character. Although the  
Internal Register Table shows Xon, Xoff Registers with eight bits of character information, the actual number of  
bits is dependent on the programmed word length. Line Control Register (LCR) bits 0-1 defines the number of  
character bits, i.e., either 5 bits, 6 bits, 7 bits, or 8 bits. The word length selected by LCR bits 0-1 also  
determines the number of bits that will be used for the special character comparison. Bit-0 in the Xon, Xoff  
Registers corresponds with the LSB bit for the receive character.  
20  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.16 Infrared Mode  
The M564 UART includes the infrared encoder and decoder compatible to the IrDA (Infrared Data Association)  
version 1.0. The IrDA 1.0 standard that stipulates the infrared encoder sends out a 3/16 of a bit wide HIGH-  
pulse for each “0” bit in the transmit data stream. This signal encoding reduces the on-time of the infrared LED,  
hence reduces the power consumption. See Figure 12 below.  
The infrared encoder and decoder are enabled by setting MCR register bit-6 to a ‘1’. When the infrared feature  
is enabled, the transmit data output, TX, idles at logic zero level. Likewise, the RX input assumes an idle level  
of logic zero from a reset and power up, see Figure 12.  
Typically, the wireless infrared decoder receives the input pulse from the infrared sensing diode on the RX pin.  
Each time it senses a light pulse, it returns HIGH to the data bit stream.  
F
IGURE 12. INFRARED  
TRANSMIT  
D
ATA  
E
NCODING AND  
R
ECEIVE  
D
ATA  
D
ECODING  
Character  
Data Bits  
1
1
1
1
1
0
0
0
0
0
TX Data  
Transmit  
IR Pulse  
(TX Pin)  
1/2 Bit Time  
Bit Time  
3/16 Bit Time  
IrEncoder-1  
Receive  
IR Pulse  
(RX pin)  
Bit Time  
1/16 Clock Delay  
1
1
1
1
1
0
0
0
0
0
RX Data  
Data Bits  
Character  
IRdecoder-1  
21  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
2.17 Sleep Mode with Auto Wake-Up  
REV. 1.0.0  
The M564 supports low voltage system designs, hence, a sleep mode is included to reduce its power  
consumption when the chip is not actively used.  
All of these conditions must be satisfied for the M564 to enter sleep mode:  
no interrupts pending for all four channels of the M564 (ISR bit-0 = 1)  
sleep mode of all channels are enabled (IER bit-4 = 1)  
modem inputs are not toggling (MSR bits 0-3 = 0)  
RX input pins are idling HIGH  
The M564 stops its crystal oscillator to conserve power in the sleep mode. User can check the XTAL2 pin for  
no clock output as an indication that the device has entered the sleep mode.  
The M564 resumes normal operation by any of the following:  
a receive data start bit transition (HIGH to LOW)  
a data byte is loaded to the transmitter, THR or FIFO  
a change of logic state on any of the modem or general purpose serial inputs: CTS#, DSR#, CD#, RI#  
If the M564 is awakened by any one of the above conditions, it will return to the sleep mode automatically after  
all interrupting conditions have been serviced and cleared. If the M564 is awakened by the modem inputs, a  
read to the MSR is required to reset the modem inputs. In any case, the sleep mode will not be entered while  
an interrupt is pending from any channel. The M564 will stay in the sleep mode of operation until it is disabled  
by setting IER bit-4 to a logic 0.  
If the address lines, data bus lines, IOW#, IOR#, CSA#, CSB#, CSC#, CSD# and modem input lines remain  
steady when the M564 is in sleep mode, the maximum current will be in the microamp range as specified in the  
DC Electrical Characteristics on page 40. If the input lines are floating or are toggling while the M564 is in  
sleep mode, the current can be up to 100 times more. If any of those signals are toggling or floating, then an  
external buffer would be required to keep the address, data and control lines steady to achieve the low current.  
A word of caution: owing to the starting up delay of the crystal oscillator after waking up from sleep mode, the  
first few receive characters may be lost. Also, make sure the RX A-D pins are idling HIGH or “marking”  
condition during sleep mode. This may not occur when the external interface transceivers (RS-232, RS-485 or  
another type) are also put to sleep mode and cannot maintain the “marking” condition. To avoid this, the  
system design engineer can use a 47k ohm pull-up resistor on each of the RX A-D inputs.  
2.18  
Internal Loopback  
The M564 UART provides an internal loopback capability for system diagnostic purposes. The internal  
loopback mode is enabled by setting MCR register bit-4 to logic 1. All regular UART functions operate normally.  
Figure 13 shows how the modem port signals are re-configured. Transmit data from the transmit shift register  
output is internally routed to the receive shift register input allowing the system to receive the same data that it  
was sending. The TX pin is held HIGH or mark condition while RTS# and DTR# are de-asserted, and CTS#,  
DSR# CD# and RI# inputs are ignored. Caution: the RX input must be held HIGH during loopback test else  
upon exiting the loopback test the UART may detect and report a false “break” signal.  
22  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
F
IGURE 13. INTERNAL LOOP BACK IN CHANNELS A - D  
VCC  
TX A-D  
Transmit Shift Register  
(THR/FIFO)  
MCR bit-4=1  
Receive Shift Register  
(RHR/FIFO)  
RX A-D  
VCC  
RTS# A-D  
RTS#  
CTS#  
CTS# A-D  
VCC  
DTR# A-D  
DTR#  
DSR#  
RI#  
DSR# A-D  
OP1#  
RI# A-D  
OP2#  
CD#  
CD# A-D  
23  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
3.0 UART INTERNAL REGISTERS  
REV. 1.0.0  
Each UART channel in the M564 has its own set of configuration registers selected by address lines A0, A1  
and A2 with a specific channel selected (See Table 1 and Table 2). The complete register set is shown on  
Table 9 and Table 10.  
TABLE 9: UART CHANNEL A AND B UART INTERNAL REGISTERS  
A2,A1,A0 ADDRESSES  
R
EGISTER  
READ/WRITE  
COMMENTS  
16C550 COMPATIBLE  
REGISTERS  
0
0 0  
RHR - Receive Holding Register  
Read-only  
Write-only  
LCR[7] = 0  
THR - Transmit Holding Register  
0
0 0  
0 1  
1 0  
0 1  
1 0  
DLL - Divisor LSB  
Read/Write  
Read/Write  
Read/Write  
Read/Write  
0
0
0
0
DLM - Divisor MSB  
LCR[7] = 1, LCR 0xBF  
DLD - Divisor Fractional  
IER - Interrupt Enable Register  
LCR[7] = 0  
ISR - Interrupt Status Register  
FCR - FIFO Control Register  
Read-only  
Write-only  
0
1
1
1
1
1 1  
0 0  
0 1  
1 0  
1 1  
LCR - Line Control Register  
MCR - Modem Control Register  
LSR - Line Status Register  
MSR - Modem Status Register  
SPR - Scratch Pad Register  
Read/Write  
Read/Write  
Read/Write  
Read/Write  
Read/Write  
LCR[7] = 0  
E
NHANCED REGISTERS  
0
1
1
1
1
1 0  
0 0  
0 1  
1 0  
1 1  
EFR - Enhanced Function Reg  
Xon-1 - Xon Character 1  
Xon-2 - Xon Character 2  
Xoff-1 - Xoff Character 1  
Xoff-2 - Xoff Character 2  
Read/Write  
Read/Write  
Read/Write  
Read/Write  
Read/Write  
LCR = 0xBF  
24  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
TABLE 10: INTERNAL REGISTERS DESCRIPTION.  
S
HADED BITS ARE ENABLED WHEN EFR BIT-4=1  
A
DDRESS  
R
EG  
R
EAD  
/
BIT-7  
BIT-6  
B
IT-5  
BIT-4  
B
IT-3  
BIT-2  
BIT-1  
BIT-0  
COMMENT  
A2-A0  
NAME  
W
RITE  
16C550 Compatible Registers  
0 0 0  
0 0 0  
0 0 1  
RHR  
THR  
RD  
Bit-7  
Bit-7  
0/  
Bit-6  
Bit-6  
0/  
Bit-5  
Bit-5  
0/  
Bit-4  
Bit-4  
0/  
Bit-3  
Bit-3  
Bit-2  
Bit-2  
Bit-1  
Bit-1  
Bit-0  
Bit-0  
WR  
IER RD/WR  
Modem RXLine  
Stat. Int.  
Enable  
TX  
Empty  
Int  
RX  
Data  
Int.  
Stat.  
Int.  
CTS#  
Int.  
Enable Enable  
RTS# Xoff Int.  
Int.  
Sleep  
Mode  
Enable  
Enable  
Enable Enable Enable  
LCR[7] = 0  
0 1 0  
0 1 0  
ISR  
RD  
FIFOs  
Enabled Enabled  
FIFOs  
0/  
0/  
INT  
INT  
INT  
INT  
Source Source Source Source  
Bit-3  
RTS  
CTS  
Int  
Xoff  
Int  
Bit-2  
Bit-1  
Bit-0  
FCR  
WR RXFIFO RXFIFO  
Trigger Trigger  
0/  
0/  
DMA  
Mode  
Enable  
TX  
FIFO  
Reset Reset  
RX  
FIFOs  
FIFO Enable  
TXFIFO TXFIFO  
Trigger  
Trigger  
0 1 1  
1 0 0  
LCR RD/WR Divisor Set TX  
Set  
Even  
Parity  
Parity  
Enable  
Stop  
Bits  
Word  
Length Length  
Bit-1 Bit-0  
Word  
Enable  
Break  
Parity  
MCR RD/WR  
0/  
0/  
0/  
Internal INT Out- Rsvd  
Lopback  
Enable  
RTS# DTR#  
Output Output  
Control Control  
put  
Enable  
(OP1#)  
BRG  
Pres-  
caler  
IR Mode Xon Any  
ENable  
(OP2#)  
1 0 1  
LSR RD/WR RXFIFO THR &  
THR  
RX Break  
RX  
RX  
RX  
RX  
Global  
Error  
TSR  
Empty  
Empty  
Parity Over-  
Data LCR[7] = 0  
Ready  
Framing  
Error  
Error  
run  
Error  
1 1 0  
1 1 1  
MSR RD/WR  
SPR RD/WR  
CD#  
Input  
RI#  
Input  
DSR#  
Input  
CTS#  
Input  
Delta  
CD#  
Delta  
RI#  
Delta  
DSR# CTS#  
Delta  
Bit-7  
Bit-6  
Bit-5  
Bit-4  
Bit-3  
Bit-2  
Bit-1  
Bit-0  
Baud Rate Generator Divisor  
0 0 0  
0 0 1  
0 1 0  
DLL RD/WR  
DLM RD/WR  
Bit-7  
Bit-7  
Bit-6  
Bit-6  
Bit-5  
Bit-5  
Bit-4  
Bit-4  
Bit-3  
Bit-3  
Bit-3  
Bit-2  
Bit-2  
Bit-2  
Bit-1  
Bit-1  
Bit-1  
Bit-0  
Bit-0  
LCR[7]=1  
LCR0xBF  
DLD RD/WR Rsvd  
Rsvd 4X Mode 8X Mode  
Bit-0 LCR[7] = 1  
LCR0xBF  
EFR[4] = 1  
25  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
TABLE 10: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1  
A
DDRESS  
R
EG  
R
EAD  
/
BIT-7  
BIT-6  
B
IT-5  
BIT-4  
B
IT-3  
BIT-2  
B
IT-1  
BIT-0  
COMMENT  
A2-A0  
NAME  
W
RITE  
Enhanced Registers  
0 1 0  
EFR RD/WR  
Auto  
CTS#  
Enable Enable  
Auto  
RTS#  
Special  
Char  
Select  
Enable  
Soft-  
ware  
Flow  
Cntl  
Soft-  
ware  
Flow  
Cntl  
Soft-  
ware  
Flow  
Cntl  
Soft-  
ware  
Flow  
Cntl  
IER [7:4],  
ISR [5:4],  
FCR[5:4],  
MCR[7:5],  
DLD  
Bit-2  
Bit-1  
Bit-0  
Bit-3  
LCR=0XBF  
1 0 0  
1 0 1  
1 1 0  
1 1 1  
XON1 RD/WR  
XON2 RD/WR  
XOFF1 RD/WR  
XOFF2 RD/WR  
Bit-7  
Bit-7  
Bit-7  
Bit-7  
Bit-6  
Bit-6  
Bit-6  
Bit-6  
Bit-5  
Bit-5  
Bit-5  
Bit-5  
Bit-4  
Bit-4  
Bit-4  
Bit-4  
Bit-3  
Bit-3  
Bit-3  
Bit-3  
Bit-2  
Bit-2  
Bit-2  
Bit-2  
Bit-1  
Bit-1  
Bit-1  
Bit-1  
Bit-0  
Bit-0  
Bit-0  
Bit-0  
4.0 INTERNAL REGISTER DESCRIPTIONS  
4.1 Receive Holding Register (RHR) - Read- Only  
SEE”RECEIVER” ON PAGE 17.  
4.2 Transmit Holding Register (THR) - Write-Only  
SEE”TRANSMITTER” ON PAGE 15.  
4.3 Interrupt Enable Register (IER) - Read/Write  
The Interrupt Enable Register (IER) masks the interrupts from receive data ready, transmit empty, line status  
and modem status registers. These interrupts are reported in the Interrupt Status Register (ISR).  
4.3.1  
IER versus Receive FIFO Interrupt Mode Operation  
When the receive FIFO (FCR BIT-0 = 1) and receive interrupts (IER BIT-0 = 1) are enabled, the RHR interrupts  
(see ISR bits 2 and 3) status will reflect the following:  
A. The receive data available interrupts are issued to the host when the FIFO has reached the programmed  
trigger level. It will be cleared when the FIFO drops below the programmed trigger level.  
B. FIFO level will be reflected in the ISR register when the FIFO trigger level is reached. Both the ISR register  
status bit and the interrupt will be cleared when the FIFO drops below the trigger level.  
C. The receive data ready bit (LSR BIT-0) is set as soon as a character is transferred from the shift register to  
the receive FIFO. It is reset when the FIFO is empty.  
26  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
4.3.2  
IER versus Receive/Transmit FIFO Polled Mode Operation  
When FCR BIT-0 equals a logic 1 for FIFO enable; resetting IER bits 0-3 enables the XR16M564 in the FIFO  
polled mode of operation. Since the receiver and transmitter have separate bits in the LSR either or both can  
be used in the polled mode by selecting respective transmit or receive control bit(s).  
A. LSR BIT-0 indicates there is data in RHR or RX FIFO.  
B. LSR BIT-1 indicates an overrun error has occurred and that data in the FIFO may not be valid.  
C. LSR BIT 2-4 provides the type of receive data errors encountered for the data byte in RHR, if any.  
D. LSR BIT-5 indicates THR is empty.  
E. LSR BIT-6 indicates when both the transmit FIFO and TSR are empty.  
F. LSR BIT-7 indicates a data error in at least one character in the RX FIFO.  
IER[0]: RHR Interrupt Enable  
The receive data ready interrupt will be issued when RHR has a data character in the non-FIFO mode or when  
the receive FIFO has reached the programmed trigger level in the FIFO mode.  
Logic 0 = Disable the receive data ready interrupt (default).  
Logic 1 = Enable the receiver data ready interrupt.  
IER[1]: THR Interrupt Enable  
This bit enables the Transmit Ready interrupt which is issued whenever the THR becomes empty in the non-  
FIFO mode or when data in the FIFO falls below the programmed trigger level in the FIFO mode. If the THR is  
empty when this bit is enabled, an interrupt will be generated.  
Logic 0 = Disable Transmit Ready interrupt (default).  
Logic 1 = Enable Transmit Ready interrupt.  
IER[2]: Receive Line Status Interrupt Enable  
If any of the LSR register bits 1, 2, 3 or 4 is a logic 1, it will generate an interrupt to inform the host controller  
about the error status of the current data byte in FIFO. LSR bit-1 generates an interrupt immediately when an  
overrun occurs. LSR bits 2-4 generate an interrupt when the character in the RHR has an error.  
Logic 0 = Disable the receiver line status interrupt (default).  
Logic 1 = Enable the receiver line status interrupt.  
IER[3]: Modem Status Interrupt Enable  
Logic 0 = Disable the modem status register interrupt (default).  
Logic 1 = Enable the modem status register interrupt.  
IER[4]: Sleep Mode Enable (requires EFR[4] = 1)  
Logic 0 = Disable Sleep Mode (default).  
Logic 1 = Enable Sleep Mode. See Sleep Mode section for further details.  
IER[5]: Xoff Interrupt Enable (requires EFR[4]=1)  
Logic 0 = Disable the software flow control, receive Xoff interrupt. (default)  
Logic 1 = Enable the software flow control, receive Xoff interrupt. See Software Flow Control section for  
details.  
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XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
IER[6]: RTS# Output Interrupt Enable (requires EFR[4]=1)  
REV. 1.0.0  
Logic 0 = Disable the RTS# interrupt (default).  
Logic 1 = Enable the RTS# interrupt. The UART issues an interrupt when the RTS# pin makes a transition  
from LOW to HIGH (if enabled by EFR bit-6).  
IER[7]: CTS# Input Interrupt Enable (requires EFR[4]=1)  
Logic 0 = Disable the CTS# interrupt (default).  
Logic 1 = Enable the CTS# interrupt. The UART issues an interrupt when CTS# pin makes a transition from  
LOW to HIGH (if enabled by EFR bit-7).  
4.4  
Interrupt Status Register (ISR) - Read-Only  
The UART provides multiple levels of prioritized interrupts to minimize external software interaction. The  
Interrupt Status Register (ISR) provides the user with six interrupt status bits. Performing a read cycle on the  
ISR will give the user the current highest pending interrupt level to be serviced, others are queued up to be  
serviced next. No other interrupts are acknowledged until the pending interrupt is serviced. The Interrupt  
Source Table, Table 11, shows the data values (bit 0-5) for the interrupt priority levels and the interrupt sources  
associated with each of these interrupt levels.  
4.4.1  
Interrupt Generation:  
LSR is by any of the LSR bits 1, 2, 3 and 4.  
RXRDY is by RX trigger level.  
RXRDY Time-out is by a 4-char plus 12 bits delay timer.  
TXRDY is by TX trigger level or TX FIFO empty.  
MSR is by any of the MSR bits 0, 1, 2 and 3.  
Receive Xoff/Special character is by detection of a Xoff or Special character.  
CTS# is when the remote transmitter toggles the input pin (from LOW to HIGH) during auto CTS flow control.  
RTS# is when its receiver toggles the output pin (from LOW to HIGH) during auto RTS flow control.  
4.4.2  
Interrupt Clearing:  
LSR interrupt is cleared by a read to the LSR register.  
RXRDY interrupt is cleared by reading data until FIFO falls below the trigger level.  
RXRDY Time-out interrupt is cleared by reading RHR.  
TXRDY interrupt is cleared by a read to the ISR register or writing to THR.  
MSR interrupt is cleared by a read to the MSR register.  
Xoff interrupt is cleared by a read to the ISR register or when XON character(s) is received.  
Special character interrupt is cleared by a read to ISR register or after next character is received.  
RTS# and CTS# flow control interrupts are cleared by a read to the MSR register.  
28  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
]
T
ABLE 11: INTERRUPT  
S
OURCE AND  
P
RIORITY  
L
EVEL  
OURCE OF INTERRUPT  
P
RIORITY  
ISR REGISTER  
STATUS  
BITS  
S
LEVEL  
BIT-5  
BIT-4  
BIT-3  
BIT-2  
BIT-1  
BIT-0  
1
2
3
4
5
6
7
-
0
0
0
1
1
0
LSR (Receiver Line Status Register)  
RXRDY (Receive Data Time-out)  
RXRDY (Received Data Ready)  
TXRDY (Transmit Ready)  
0
0
1
1
0
0
0
0
0
1
0
0
0
0
0
0
1
0
0
0
0
0
0
0
MSR (Modem Status Register)  
RXRDY (Received Xoff or Special character)  
CTS#, RTS# change of state  
None (default)  
0
1
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
1
ISR[0]: Interrupt Status  
Logic 0 = An interrupt is pending and the ISR contents may be used as a pointer to the appropriate interrupt  
service routine.  
Logic 1 = No interrupt pending (default condition).  
ISR[3:1]: Interrupt Status  
These bits indicate the source for a pending interrupt at interrupt priority levels (See Interrupt Source  
Table 11).  
ISR[4]: Interrupt Status (requires EFR bit-4 = 1)  
This bit is enabled when EFR bit-4 is set to a logic 1. ISR bit-4 indicates that the receiver detected a data match  
of the Xoff character(s) or a special character.  
ISR[5]: Interrupt Status (requires EFR bit-4 = 1)  
ISR bit-5 indicates that CTS# or RTS# has changed state from LOW to HIGH.  
ISR[7:6]: FIFO Enable Status  
These bits are set to a logic 0 when the FIFOs are disabled. They are set to a logic 1 when the FIFOs are  
enabled.  
4.5  
FIFO Control Register (FCR) - Write-Only  
This register is used to enable the FIFOs, clear the FIFOs, set the transmit/receive FIFO trigger levels, and  
select the DMA mode. The DMA, and FIFO modes are defined as follows:  
FCR[0]: TX and RX FIFO Enable  
Logic 0 = Disable the transmit and receive FIFO (default).  
Logic 1 = Enable the transmit and receive FIFOs. This bit must be set to logic 1 when other FCR bits are  
written or they will not be programmed.  
29  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
FCR[1]: RX FIFO Reset  
REV. 1.0.0  
This bit is only active when FCR bit-0 is a ‘1’.  
Logic 0 = No receive FIFO reset (default)  
Logic 1 = Reset the receive FIFO pointers and FIFO level counter logic (the receive shift register is not  
cleared or altered). This bit will return to a logic 0 after resetting the FIFO.  
FCR[2]: TX FIFO Reset  
This bit is only active when FCR bit-0 is a ‘1’.  
Logic 0 = No transmit FIFO reset (default).  
Logic 1 = Reset the transmit FIFO pointers and FIFO level counter logic (the transmit shift register is not  
cleared or altered). This bit will return to a logic 0 after resetting the FIFO.  
FCR[3]: DMA Mode Select  
Controls the behavior of the -TXRDY and -RXRDY pins. See DMA operation section for details.  
Logic 0 = Normal Operation (default).  
Logic 1 = DMA Mode.  
FCR[5:4]: Transmit FIFO Trigger Select (requires EFR bit-4 = 1)  
(logic 0 = default, TX trigger level = one)  
These 2 bits set the trigger level for the transmit FIFO. The UART will issue a transmit interrupt when the  
number of characters in the FIFO falls below the selected trigger level, or when it gets empty in case that the  
FIFO did not get filled over the trigger level on last re-load. Table 12 below shows the selections.  
FCR[7:6]: Receive FIFO Trigger Select  
(logic 0 = default, RX trigger level =1)  
These 2 bits are used to set the trigger level for the receive FIFO. The UART will issue a receive interrupt when  
the number of the characters in the FIFO crosses the trigger level. Table 12 shows the complete selections.  
TABLE 12: TRANSMIT AND  
RECEIVE FIFO TRIGGER LEVEL SELECTION  
R
ECEIVE  
T
RANSMIT  
FCR FCR FCR  
FCR  
BIT-4  
TRIGGER  
TRIGGER  
BIT-7  
BIT-6  
BIT-5  
L
EVEL  
LEVEL  
0
0
1
1
0
1
0
1
16  
8
24  
30  
0
0
1
1
0
1
0
1
8
16  
24  
30  
30  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
4.6  
Line Control Register (LCR) - Read/Write  
The Line Control Register is used to specify the asynchronous data communication format. The word or  
character length, the number of stop bits, and the parity are selected by writing the appropriate bits in this  
register.  
LCR[1:0]: TX and RX Word Length Select  
These two bits specify the word length to be transmitted or received.  
BIT-1  
BIT-0  
WORD LENGTH  
0
0
1
1
0
1
0
1
5 (default)  
6
7
8
LCR[2]: TX and RX Stop-bit Length Select  
The length of stop bit is specified by this bit in conjunction with the programmed word length.  
S
TOP BIT LENGTH  
W
ORD  
BIT-2  
LENGTH  
5,6,7,8  
5
(BIT TIME  
(S))  
0
1
1
1 (default)  
1-1/2  
2
6,7,8  
LCR[3]: TX and RX Parity Select  
Parity or no parity can be selected via this bit. The parity bit is a simple way used in communications for data  
integrity check. See Table 13 for parity selection summary below.  
Logic 0 = No parity.  
Logic 1 = A parity bit is generated during the transmission while the receiver checks for parity error of the  
data character received.  
LCR[4]: TX and RX Parity Select  
If the parity bit is enabled with LCR bit-3 set to a logic 1, LCR BIT-4 selects the even or odd parity format.  
Logic 0 = ODD Parity is generated by forcing an odd number of logic 1’s in the transmitted character. The  
receiver must be programmed to check the same format (default).  
Logic 1 = EVEN Parity is generated by forcing an even number of logic 1’s in the transmitted character. The  
receiver must be programmed to check the same format.  
31  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
LCR[5]: TX and RX Parity Select  
REV. 1.0.0  
If the parity bit is enabled, LCR BIT-5 selects the forced parity format.  
LCR BIT-5 = LOW, parity is not forced (default).  
LCR BIT-5 = HIGH and LCR BIT-4 = LOW, parity bit is forced to a logical 1 for the transmit and receive data.  
LCR BIT-5 = HIGH and LCR BIT-4 = LOW, parity bit is forced to a logical 0 for the transmit and receive data.  
TABLE 13: PARITY SELECTION  
LCR BIT-5 LCR BIT-4 LCR BIT-3  
P
ARITY SELECTION  
No parity  
X
0
0
1
1
X
0
1
0
1
0
1
1
1
1
Odd parity  
Even parity  
Force parity to mark, HIGH  
Forced parity to space, LOW  
LCR[6]: Transmit Break Enable  
When enabled, the Break control bit causes a break condition to be transmitted (the TX output is forced to a  
“space’, LOW, state). This condition remains, until disabled by setting LCR bit-6 to a logic 0.  
Logic 0 = No TX break condition. (default)  
Logic 1 = Forces the transmitter output (TX) to a “space”, LOW, for alerting the remote receiver of a line  
break condition.  
LCR[7]: Baud Rate Divisors Enable  
Baud rate generator divisor (DLL/DLM/DLD) enable.  
Logic 0 = Data registers are selected. (default)  
Logic 1 = Divisor latch registers are selected.  
4.7  
Modem Control Register (MCR) or General Purpose Outputs Control - Read/Write  
The MCR register is used for controlling the serial/modem interface signals or general purpose inputs/outputs.  
MCR[0]: DTR# Output  
The DTR# pin is a modem control output. If the modem interface is not used, this output may be used as a  
general purpose output.  
Logic 0 = Force DTR# output HIGH (default).  
Logic 1 = Force DTR# output LOW.  
MCR[1]: RTS# Output  
The RTS# pin is a modem control output and may be used for automatic hardware flow control by enabled by  
EFR bit-6. If the modem interface is not used, this output may be used as a general purpose output.  
Logic 0 = Force RTS# output HIGH (default).  
Logic 1 = Force RTS# output LOW.  
MCR[2]: Reserved  
OP1# is not available as an output pin on the M564. But it is available for use during Internal Loopback Mode.  
In the Loopback Mode, this bit is used to write the state of the modem RI# interface signal.  
32  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
MCR[3]: INT Output Enable  
Enable or disable INT outputs to become active or in three-state. This function is associated with the INTSEL  
input, see below table for details. This bit is also used to control the OP2# signal during internal loopback  
mode. INTSEL pin must be LOW during 68 mode.  
Logic 0 = INT (A-D) outputs disabled (three state) in the 16 mode (default). During internal loopback mode,  
OP2# is HIGH.  
Logic 1 = INT (A-D) outputs enabled (active) in the 16 mode. During internal loopback mode, OP2# is LOW.  
TABLE 14: INT OUTPUT MODES  
INTSEL MCR  
INT A-D OUTPUTS IN 16 MODE  
P
IN  
BIT-3  
0
0
Three-State  
Active  
0
1
1
X
Active  
MCR[4]: Internal Loopback Enable  
Logic 0 = Disable loopback mode (default).  
Logic 1 = Enable local loopback mode, see loopback section and Figure 13.  
MCR[5]: Xon-Any Enable (requires EFR bit-4 = 1)  
Logic 0 = Disable Xon-Any function (for 16C550 compatibility, default).  
Logic 1 = Enable Xon-Any function. In this mode, any RX character received will resume transmit operation.  
The RX character will be loaded into the RX FIFO , unless the RX character is an Xon or Xoff character and  
the M564 is programmed to use the Xon/Xoff flow control.  
MCR[6]: Infrared Encoder/Decoder Enable (requires EFR bit-4 = 1)  
Logic 0 = Enable the standard modem receive and transmit input/output interface. (Default)  
Logic 1 = Enable infrared IrDA receive and transmit inputs/outputs. The TX/RX output/input are routed to the  
infrared encoder/decoder. The data input and output levels conform to the IrDA infrared interface  
requirement. The RX FIFO may need to be flushed upon enable. While in this mode, the infrared TX output  
will be LOW during idle data conditions.  
MCR[7]: Clock Prescaler Select (requires EFR bit-4 = 1)  
Logic 0 = Divide by one. The input clock from the crystal or external clock is fed directly to the Programmable  
Baud Rate Generator without further modification, i.e., divide by one (default).  
Logic 1 = Divide by four. The prescaler divides the input clock from the crystal or external clock by four and  
feeds it to the Programmable Baud Rate Generator, hence, data rates become one forth.  
33  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
4.8  
Line Status Register (LSR) - Read/Write  
This register is writeable but it is not recommended. The LSR provides the status of data transfers between the  
UART and the host. If IER bit-2 is enabled, LSR bit 1 will generate an interrupt immediately and LSR bits 2-4  
will generate an interrupt when a character with an error is in the RHR.  
LSR[0]: Receive Data Ready Indicator  
Logic 0 = No data in receive holding register or FIFO (default).  
Logic 1 = Data has been received and is saved in the receive holding register or FIFO.  
LSR[1]: Receiver Overrun Flag  
Logic 0 = No overrun error (default).  
Logic 1 = Overrun error. A data overrun error condition occurred in the receive shift register. This happens  
when additional data arrives while the FIFO is full. In this case the previous data in the receive shift register  
is overwritten. Note that under this condition the data byte in the receive shift register is not transferred into  
the FIFO, therefore the data in the FIFO is not corrupted by the error.  
LSR[2]: Receive Data Parity Error Tag  
Logic 0 = No parity error (default).  
Logic 1 = Parity error. The receive character in RHR does not have correct parity information and is suspect.  
This error is associated with the character available for reading in RHR.  
LSR[3]: Receive Data Framing Error Tag  
Logic 0 = No framing error (default).  
Logic 1 = Framing error. The receive character did not have a valid stop bit(s). This error is associated with  
the character available for reading in RHR.  
LSR[4]: Receive Break Tag  
Logic 0 = No break condition (default).  
Logic 1 = The receiver received a break signal (RX was LOW for at least one character frame time). In the  
FIFO mode, only one break character is loaded into the FIFO. The break indication remains until the RX  
input returns to the idle condition, “mark” or HIGH.  
LSR[5]: Transmit Holding Register Empty Flag  
This bit is the Transmit Holding Register Empty indicator. The THR bit is set to HIGH when the last data byte is  
transferred from the transmit holding register to the transmit shift register. The bit is reset to logic 0 concurrently  
with the data loading to the transmit holding register by the host. In the FIFO mode this bit is set when the  
transmit FIFO is empty, it is cleared when the transmit FIFO contains at least 1 byte.  
LSR[6]: THR and TSR Empty Flag  
This bit is set to HIGH whenever the transmitter goes idle. It is set to LOW whenever either the THR or TSR  
contains a data character. In the FIFO mode this bit is set to HIGH whenever the transmit FIFO and transmit  
shift register are both empty.  
LSR[7]: Receive FIFO Data Error Flag  
Logic 0 = No FIFO error (default).  
Logic 1 = A global indicator for the sum of all error bits in the RX FIFO. At least one parity error, framing error  
or break indication is in the FIFO data. This bit clears when there is no more error(s) in any of the bytes in the  
RX FIFO.  
34  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
4.9  
Modem Status Register (MSR) - Read/Write  
This register is writeable but it is not recommended. The MSR provides the current state of the modem  
interface input signals. Lower four bits of this register are used to indicate the changed information. These bits  
are set to a HIGH whenever a signal from the modem changes state. These bits may be used for general  
purpose inputs when they are not used with modem signals.  
MSR[0]: Delta CTS# Input Flag  
Logic 0 = No change on CTS# input (default).  
Logic 1 = The CTS# input has changed state since the last time it was monitored. A modem status interrupt  
will be generated if MSR interrupt is enabled (IER bit-3).  
MSR[1]: Delta DSR# Input Flag  
Logic 0 = No change on DSR# input (default).  
Logic 1 = The DSR# input has changed state since the last time it was monitored. A modem status interrupt  
will be generated if MSR interrupt is enabled (IER bit-3).  
MSR[2]: Delta RI# Input Flag  
Logic 0 = No change on RI# input (default).  
Logic 1 = The RI# input has changed from LOW to HIGH, ending of the ringing signal. A modem status  
interrupt will be generated if MSR interrupt is enabled (IER bit-3).  
MSR[3]: Delta CD# Input Flag  
Logic 0 = No change on CD# input (default).  
Logic 1 = Indicates that the CD# input has changed state since the last time it was monitored. A modem  
status interrupt will be generated if MSR interrupt is enabled (IER bit-3).  
MSR[4]: CTS Input Status  
CTS# pin may function as automatic hardware flow control signal input if it is enabled and selected by Auto  
CTS (EFR bit-7). Auto CTS flow control allows starting and stopping of local data transmissions based on the  
modem CTS# signal. A HIGH on the CTS# pin will stop UART transmitter as soon as the current character has  
finished transmission, and a LOW will resume data transmission. Normally MSR bit-4 bit is the compliment of  
the CTS# input. However in the loopback mode, this bit is equivalent to the RTS# bit in the MCR register. The  
CTS# input may be used as a general purpose input when the modem interface is not used.  
MSR[5]: DSR Input Status  
Normally this bit is the complement of the DSR# input. In the loopback mode, this bit is equivalent to the DTR#  
bit in the MCR register. The DSR# input may be used as a general purpose input when the modem interface is  
not used.  
MSR[6]: RI Input Status  
Normally this bit is the complement of the RI# input. In the loopback mode this bit is equivalent to bit-2 in the  
MCR register. The RI# input may be used as a general purpose input when the modem interface is not used.  
MSR[7]: CD Input Status  
Normally this bit is the complement of the CD# input. In the loopback mode this bit is equivalent to bit-3 in the  
MCR register. The CD# input may be used as a general purpose input when the modem interface is not used.  
4.10 Scratch Pad Register (SPR) - Read/Write  
This is a 8-bit general purpose register for the user to store temporary data. The content of this register is  
preserved during sleep mode but becomes 0xFF (default) after a reset or a power off-on cycle.  
35  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
4.11 Baud Rate Generator Registers (DLL and DLM) - Read/Write  
REV. 1.0.0  
These registers make-up the value of the baud rate divisor. The concatenation of the contents of DLM and DLL  
gives the 16-bit divisor value. Then the value is added to DLD[3:0]/16 to achieve the fractional baud rate  
divisor. DLD must be enabled via EFR bit-4 before it can be accessed. See Table 15 below and See ”Section  
2.8, Programmable Baud Rate Generator with Fractional Divisor” on page 13.  
DLD[5:4]: Sampling Rate Select  
These bits select the data sampling rate. By default, the data sampling rate is 16X. The maximum data rate will  
double if the 8X mode is selected and will quadruple if the 4X mode is selected. See Table 15 below.  
TABLE 15: SAMPLING RATE SELECT  
DLD[5]  
DLD[4]  
S
AMPLING  
16X  
RATE  
0
0
1
0
1
X
8X  
4X  
DLD[7:6]: Reserved  
4.12 Enhanced Feature Register (EFR) - Read/Write  
Enhanced features are enabled or disabled using this register. Bit 0-3 provide single or dual consecutive  
character software flow control selection (see Table 16). When the Xon1 and Xon2 and Xoff1 and Xoff2 modes  
are selected, the double 8-bit words are concatenated into two sequential characters. Caution: note that  
whenever changing the TX or RX flow control bits, always reset all bits back to logic 0 (disable) before  
programming a new setting.  
EFR[3:0]: Software Flow Control Select  
Single character and dual sequential characters software flow control is supported. Combinations of software  
flow control can be selected by programming these bits.  
36  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
TABLE 16: SOFTWARE  
FLOW CONTROL FUNCTIONS  
EFR BIT-3  
EFR BIT-2  
EFR BIT-1 EFR BIT-0  
TRANSMIT AND RECEIVE SOFTWARE FLOW CONTROL  
CONT-1  
CONT-0  
CONT-3  
CONT-2  
0
0
1
0
1
X
X
X
1
0
0
0
1
1
X
X
X
0
0
X
X
X
X
0
1
0
1
0
X
X
X
X
0
No TX and RX flow control (default and reset)  
No transmit flow control  
Transmit Xon1, Xoff1  
Transmit Xon2, Xoff2  
Transmit Xon1 and Xon2, Xoff1 and Xoff2  
No receive flow control  
0
Receiver compares Xon1, Xoff1  
Receiver compares Xon2, Xoff2  
1
1
Transmit Xon1, Xoff1  
Receiver compares Xon1 or Xon2, Xoff1 or Xoff2  
0
1
0
1
1
0
1
1
1
1
1
1
Transmit Xon2, Xoff2  
Receiver compares Xon1 or Xon2, Xoff1 or Xoff2  
Transmit Xon1 and Xon2, Xoff1 and Xoff2,  
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2  
No transmit flow control,  
Receiver compares Xon1 and Xon2, Xoff1 and Xoff2  
EFR[4]: Enhanced Function Bits Enable  
Enhanced function control bit. This bit enables IER bits 4-7, ISR bits 4-5, FCR bits 4-5, MCR bits 5-7, and DLD  
to be modified. After modifying any enhanced bits, EFR bit-4 can be set to a LOW to latch the new values. This  
feature prevents legacy software from altering or overwriting the enhanced functions once set. Normally, it is  
recommended to leave it enabled, HIGH.  
Logic 0 = modification disable/latch enhanced features. IER bits 4-7, ISR bits 4-5, FCR bits 4-5, MCR bits 5-  
7, and DLD are saved to retain the user settings. After a reset, the IER bits 4-7, ISR bits 4-5, FCR bits 4-5,  
and MCR bits 5-7, and DLD are set to a LOW to be compatible with ST16C550 mode (default).  
Logic 1 = Enables the above-mentioned register bits to be modified by the user.  
EFR[5]: Special Character Detect Enable  
Logic 0 = Special Character Detect Disabled (default).  
Logic 1 = Special Character Detect Enabled. The UART compares each incoming receive character with  
data in Xoff-2 register. If a match exists, the receive data will be transferred to FIFO and ISR bit-4 will be set  
to indicate detection of the special character. Bit-0 corresponds with the LSB bit of the receive character. If  
flow control is set for comparing Xon1, Xoff1 (EFR [1:0]= ‘10’) then flow control and special character work  
normally. However, if flow control is set for comparing Xon2, Xoff2 (EFR[1:0]= ‘01’) then flow control works  
normally, but Xoff2 will not go to the FIFO, and will generate an Xoff interrupt and a special character  
interrupt, if enabled via IER bit-5.  
37  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
EFR[6]: Auto RTS Flow Control Enable  
REV. 1.0.0  
RTS# output may be used for hardware flow control by setting EFR bit-6 to logic 1. When Auto RTS is  
selected, an interrupt will be generated when the receive FIFO is filled to the programmed trigger level and  
RTS de-asserts HIGH at the next upper trigger level/hysteresis level. RTS# will return LOW when FIFO data  
falls below the next lower trigger level/hysteresis level. The RTS# output must be asserted (LOW) before the  
auto RTS can take effect. RTS# pin will function as a general purpose output when hardware flow control is  
disabled.  
Logic 0 = Automatic RTS flow control is disabled (default).  
Logic 1 = Enable Automatic RTS flow control.  
EFR[7]: Auto CTS Flow Control Enable  
Automatic CTS Flow Control.  
Logic 0 = Automatic CTS flow control is disabled (default).  
Logic 1 = Enable Automatic CTS flow control. Data transmission stops when CTS# input de-asserts to logic  
1. Data transmission resumes when CTS# returns to a LOW.  
4.13 Software Flow Control Registers (XOFF1, XOFF2, XON1, XON2) - Read/Write  
These registers are used as the programmable software flow control characters xoff1, xoff2, xon1, and xon2.  
For more details, see Table 8.  
38  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
TABLE 17: UART RESET CONDITIONS FOR CHANNELS A-D  
REGISTERS  
RESET STATE  
DLM, DLL  
DLM = 0x00 and DLL = 0x01. Only resets to these val-  
ues during a power up. They do not reset when the  
Reset Pin is asserted.  
DLD  
RHR  
THR  
IER  
Bits 7-0 = 0x00  
Bits 7-0 = 0xXX  
Bits 7-0 = 0xXX  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
Bits 7-0 = 0x01  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
Bits 7-0 = 0x60  
FCR  
ISR  
LCR  
MCR  
LSR  
MSR  
Bits 3-0 = Logic 0  
Bits 7-4 = Logic levels of the inputs inverted  
SPR  
EFR  
Bits 7-0 = 0xFF  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
Bits 7-0 = 0x00  
RESET STATE  
HIGH  
XON1  
XON2  
XOFF1  
XOFF2  
I/O SIGNALS  
TX  
RTS#  
HIGH  
DTR#  
HIGH  
RXRDY#  
TXRDY#  
HIGH  
LOW  
INT  
XR16M564 = Three-State Condition (INTSEL = LOW)  
XR16M564 = LOW (INTSEL = HIGH)  
XR16M564D = LOW  
(16 Mode)  
IRQ#  
Three-State Condition (INTSEL = LOW)  
(68 Mode)  
39  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
ABSOLUTE MAXIMUM RATINGS  
Power Supply Range  
Voltage at Any Pin  
4 Volts  
GND-0.3 V to 4 V  
-40o to +85oC  
Operating Temperature  
-65o to +150oC  
500 mW  
Storage Temperature  
Package Dissipation  
TYPICAL PACKAGE THERMAL RESISTANCE DATA (MARGIN OF ERROR: ± 15%)  
theta-ja = 28oC/W, theta-jc = 10.5oC/W  
Thermal Resistance (48-QFN)  
theta-ja = 49oC/W, theta-jc = 10oC/W  
Thermal Resistance (64-LQFP)  
theta-ja = 39oC/W, theta-jc = 17oC/W  
Thermal Resistance (68-PLCC)  
theta-ja = 37oC/W, theta-jc = 7oC/W  
Thermal Resistance (80-LQFP)  
ELECTRICAL CHARACTERISTICS  
DC ELECTRICAL CHARACTERISTICS  
U
NLESS OTHERWISE NOTED: TA = -40O TO +85OC, VCC IS 1.62 TO 3.63V  
L
IMITS  
L
IMITS  
LIMITS  
S
OL  
YMB  
P
ARAMETER  
1.8V  
2.5V  
3.3V  
UNITS  
CONDITIONS  
M
IN  
M
AX  
M
IN  
M
AX  
M
IN  
MAX  
VILCK Clock Input Low Level  
VIHCK Clock Input High Level  
-0.3  
1.4  
0.3  
VCC  
0.2  
-0.3  
2.0  
0.2  
VCC  
0.6  
-0.3  
2.4  
0.6  
VCC  
0.8  
V
V
V
V
VIL  
VIH  
VOL  
Input Low Voltage  
Input High Voltage  
Output Low Voltage  
-0.3  
1.4  
-0.3  
2.0  
-0.3  
2.2  
VCC  
VCC  
VCC  
0.4  
V
V
V
IOL = 4 mA  
IOL = 2 mA  
IOL = 1.5 mA  
0.4  
0.4  
VOH Output High Voltage  
2.0  
V
V
V
IOH = -1 mA  
1.8  
IOH = -400 uA  
IOH = -200 uA  
1.4  
IIL  
IIH  
Input Low Leakage Current  
±15  
±15  
5
±15  
±15  
5
±15  
±15  
5
uA  
uA  
pF  
Input High Leakage Current  
Input Pin Capacitance  
Power Supply Current  
CIN  
ICC  
1
1.5  
200  
2
mA Ext Clk = 2MHz  
uA See Test 1  
ISLEEP Sleep Current  
150  
250  
Test 1: The following inputs remain steady at VCC or GND state to minimize Sleep current: A0-A2, D0-D7, IOR#, IOW#,  
CSA#, CSB#, CSC#, and CSD#. Also, RXA, RXB, RXC, and RXD inputs must idle at HIGH while asleep.  
40  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
AC ELECTRICAL CHARACTERISTICS  
TA = -40O TO +85OC, VCC IS 1.62 TO 3.63V, 70  
P
F
LOAD WHERE APPLICABLE  
IMITS IMITS  
L
L
LIMITS  
S
YMBOL  
P
ARAMETER  
1.8V ± 10%  
2.5V ± 10%  
3.3V ± 10%  
UNIT  
M
IN  
MAX  
M
IN  
MAX  
M
IN  
MAX  
XTAL1  
ECLK  
TECLK  
UART Crystal Frequency  
External Clock Frequency  
External Clock Time Period  
24  
24  
24  
MHz  
MHz  
ns  
32  
50  
64  
15  
0
10  
0
7
0
0
TAS  
TAH  
Address Setup Time (16 Mode)  
Address Hold Time (16 Mode)  
Chip Select Width (16 Mode)  
IOR# Strobe Width (16 Mode)  
Read Cycle Delay (16 Mode)  
Data Access Time (16 Mode)  
Data Disable Time (16 Mode)  
IOW# Strobe Width (16 Mode)  
Write Cycle Delay (16 Mode)  
Data Setup Time (16 Mode)  
Data Hold Time (16 Mode)  
Address Setup (68 Mode)  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
ns  
0
0
TCS  
100  
100  
100  
65  
65  
65  
50  
50  
50  
TRD  
TDY  
TRDV  
TDD  
95  
15  
60  
15  
45  
15  
TWR  
TDY  
100  
100  
15  
3
65  
65  
10  
3
50  
50  
10  
3
TDS  
TDH  
TADS  
TADH  
TRWS  
TRDA  
TRDH  
TWDS  
TWDH  
TRWH  
0
0
0
Address Hold (68 Mode)  
0
0
0
R/W# Setup to CS# (68 Mode)  
Data Access Time (68 mode)  
Data Disable Time (68 mode)  
Write Data Setup (68 mode)  
Write Data Hold (68 Mode)  
0
0
0
95  
15  
60  
15  
45  
15  
15  
3
10  
5
10  
5
CS# De-asserted to R/W# De-  
asserted (68 Mode)  
3
3
3
TCSL  
TCSD  
TWDO  
TMOD  
CS# Strobe Width (68 Mode)  
CS# Cycle Delay (68 Mode)  
Delay From IOW# To Output  
100  
100  
65  
65  
50  
50  
ns  
ns  
ns  
ns  
50  
50  
50  
50  
50  
50  
Delay To Set Interrupt From MODEM  
Input  
41  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
AC ELECTRICAL CHARACTERISTICS  
REV. 1.0.0  
TA = -40O TO +85OC, VCC IS 1.62 TO 3.63V, 70  
P
F
LOAD WHERE APPLICABLE  
IMITS IMITS  
L
L
LIMITS  
S
YMBOL  
P
ARAMETER  
1.8V ± 10%  
2.5V ± 10%  
3.3V ± 10%  
UNIT  
M
IN  
MAX  
M
IN  
MAX  
M
IN  
MAX  
TRSI  
TSSI  
TRRI  
TSI  
Delay To Reset Interrupt From IOR#  
Delay From Stop To Set Interrupt  
Delay From IOR# To Reset Interrupt  
Delay From Start To Interrupt  
50  
50  
50  
ns  
Bclk  
ns  
1
1
1
45  
45  
24  
45  
45  
24  
45  
45  
24  
ns  
TINT  
Delay From Initial INT Reset To  
Transmit Start  
8
8
8
Bclk  
TWRI  
TSSR  
TRR  
Delay From IOW# To Reset Interrupt  
Delay From Stop To Set RXRDY#  
Delay From IOR# To Reset RXRDY#  
Delay From IOW# To Set TXRDY#  
45  
1
45  
1
45  
1
ns  
Bclk  
ns  
45  
45  
8
45  
45  
8
45  
45  
8
TWT  
ns  
TSRT  
Delay From Center of Start To Reset  
TXRDY#  
Bclk  
TRST  
Bclk  
Reset Pulse Width  
Baud Clock  
40  
40  
40  
ns  
16X or 8X or 4X of data rate  
Hz  
F
IGURE 14. CLOCK TIMING  
CLK  
CLK  
EXTERNAL  
CLOCK  
OSC  
42  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
F
IGURE 15. MODEM INPUT/OUTPUT TIMING FOR CHANNELS A-D  
IO W #  
IO W  
A c tiv e  
T W  
D O  
R T S #  
D T R #  
C h a n g e o f s ta te  
C h a n g e o f s ta te  
C D #  
C T S #  
D S R #  
C h a n g e o f s ta te  
C h a n g e o f s ta te  
T M O D  
T M O D  
IN T  
A c tiv e  
A c tiv e  
A c tiv e  
A c tiv e  
T R S I  
IO R #  
A c tiv e  
A c tiv e  
T M O D  
C h a n g e o f s ta te  
R I#  
F
IGURE 16. 16 MODE (INTEL) DATA  
B
US  
R
EAD  
TIMING FOR  
C
HANNELS A-D  
A0-A7  
CS#  
Valid Address  
TCS  
Valid Address  
TCS  
TAS  
TAS  
TAH  
TAH  
TDY  
TRD  
TRD  
IOR#  
D0-D7  
TDD  
TDD  
TRDV  
TRDV  
Valid Data  
Valid Data  
RDTm  
43  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
F
IGURE 17. 16 MODE (INTEL) DATA  
B
US  
WRITE  
TIMING FOR  
C
HANNELS A-D  
A0-A7  
CS#  
Valid Address  
TCS  
Valid Address  
TCS  
TAS  
TAS  
TAH  
TAH  
TDY  
TWR  
TWR  
IOW#  
D0-D7  
TDH  
TDH  
TDS  
Valid Data  
TDS  
Valid Data  
16Write  
F
IGURE 18. 68 MODE (MOTOROLA) DATA BUS READ TIMING FOR CHANNELS A-D  
A0-A7  
CS#  
Valid Address  
Valid Address  
TADS  
TCSL  
TADH  
T
CSD  
T
RWS  
T
RWH  
R/W#  
D0-D7  
T
RDH  
TRDA  
Valid Data  
Valid Data  
68Read  
44  
XR16M564/564D  
REV. 1.0.0  
IGURE 19. 68 MODE (MOTOROLA) DATA  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
F
B
US  
WRITE  
T
IMING FOR  
C
HANNELS A-D  
A0-A7  
CS#  
Valid Address  
Valid Address  
TADS  
TCSL  
T
ADH  
T
CSD  
T
RWS  
T
RWH  
T
R/W#  
D0-D7  
WDH  
T
WDS  
Valid Data  
Valid Data  
68Write  
F
IGURE 20. RECEIVE  
R
EADY & INTERRUPT  
TIMING [NON-FIFO MODE] FOR CHANNELS A-D  
RX  
Stop  
Bit  
Start  
Bit  
D0:D7  
D0:D7  
D0:D7  
TSSR  
TSSR  
TSSR  
1 Byte  
1 Byte  
1 Byte  
in RHR  
in RHR  
in RHR  
INT  
TSSR  
TSSR  
TSSR  
Active  
Data  
Active  
Data  
Active  
Data  
RXRDY#  
Ready  
Ready  
Ready  
TRR  
TRR  
TRR  
IOR#  
(Reading data  
out of RHR)  
RXNFM  
45  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
F
IGURE 21. TRANSMIT  
R
EADY & INTERRUPT  
TIMING [NON-FIFO MODE] FOR CHANNELS A-D  
TX  
(Unloading)  
Stop  
Bit  
Start  
Bit  
D0:D7  
D0:D7  
D0:D7  
IER[1]  
enabled  
ISR is read  
ISR is read  
ISR is read  
INT*  
TWRI  
TWRI  
TWRI  
TSRT  
TSRT  
TSRT  
TXRDY#  
TWT  
TWT  
TWT  
IOW#  
(Loading data  
into THR)  
*INT is cleared when the ISR is read or when data is loaded into the THR.  
TXNonFIFO  
F
IGURE 22. RECEIVE  
R
EADY & INTERRUPT  
TIMING [FIFO MODE, DMA DISABLED  
]
FOR CHANNELS A-D  
Start  
Bit  
RX  
S
S
S
S
T
D0:D7  
D0:D7  
D0:D7  
T
D0:D7  
TSSI  
D0:D7  
S
T
S
D0:D7  
T
D0:D7  
T
Stop  
Bit  
RX FIFO drops  
below RX  
Trigger Level  
INT  
TSSR  
FIFO  
Empties  
RX FIFO fills up to RX  
Trigger Level or RX Data  
Timeout  
RXRDY#  
First Byte is  
Received in  
RX FIFO  
TRRI  
TRR  
IOR#  
(Reading data out  
of RX FIFO)  
RXINTDMA#  
46  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
F
IGURE 23. RECEIVE  
R
EADY & INTERRUPT  
TIMING [FIFO MODE, DMA ENABLED  
]
FOR  
C
HANNELS A-D  
Start  
Bit  
Stop  
Bit  
RX  
S
S
S
S
T
D0:D7  
D0:D7  
D0:D7  
T
D0:D7  
D0:D7  
S
T
S
D0:D7  
T
D0:D7  
T
RX FIFO drops  
below RX  
TSSI  
Trigger Level  
INT  
RX FIFO fills up to RX  
Trigger Level or RX Data  
Timeout  
TSSR  
FIFO  
Empties  
RXRDY#  
TRRI  
TRR  
IOR#  
(Reading data out  
of RX FIFO)  
RXFIFODMA  
F
IGURE 24. TRANSMIT  
R
EADY & INTERRUPT  
TIMING [FIFO MODE, DMA MODE  
D
ISABLED] FOR CHANNELS A-D  
Stop  
Bit  
Start  
Bit  
Last Data Byte  
Transmitted  
TX FIFO  
Empty  
TX  
(Unloading)  
T
S
S
S
S
T
S
D0:D7  
D0:D7  
T
S
D0:D7  
T
D0:D7  
T
D0:D7  
T
D0:D7  
T
ISR is read  
TSI  
IER[1]  
enabled  
ISR is read  
TSRT  
INT*  
TX FIFO  
Empty  
TX FIFO fills up  
to trigger level  
TX FIFO drops  
below trigger level  
TWRI  
Data in  
TX FIFO  
TXRDY#  
TWT  
IOW#  
(Loading data  
into FIFO)  
*INT is cleared when the ISR is read or when TX FIFO fills up to the trigger level.  
TXDMA#  
47  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
F
IGURE 25. TRANSMIT  
R
EADY & INTERRUPT  
TIMING [FIFO MODE, DMA MODE  
E
NABLED] FOR CHANNELS A-D  
Stop  
Bit  
Start  
Bit  
Last Data Byte  
Transmitted  
TX  
(Unloading)  
S
D0:D7  
S
D0:D7  
S
S
T
T
D0:D7  
D0:D7  
S
D0:D7  
T
D0:D7  
T
S D0:D7  
T
T
IER[1]  
enabled  
ISR Read  
ISR Read  
TSI  
TSRT  
INT*  
TX FIFO fills up  
to trigger level  
TX FIFO drops  
below trigger level  
TWRI  
At least 1  
empty location  
in FIFO  
TX FIFO  
Full  
TXRDY#  
TWT  
IOW#  
(Loading data  
into FIFO)  
*INT cleared when the ISR is read or when TX FIFO fills up to trigger level.  
TXDMA  
48  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
PACKAGE DIMENSIONS  
48 LEAD QUAD FLAT NO LEAD (7 x 7 x 0.9 mm, 0.50 mm pitch QFN)  
Note: The actual center pad is  
metallic and the size (D2) is  
device-dependent with a typical  
tolerance of 0.3mm. The lead  
may be half-etched terminal.  
Note: The control dimension is the millimeter column  
INCHES  
MAX  
MILLIMETERS  
SYMBOL  
MIN  
MIN  
0.80  
0.00  
0.15  
6.85  
5.10  
0.18  
MAX  
1.00  
0.05  
0.25  
7.15  
5.30  
0.30  
A
A1  
A3  
D
0.031  
0.000  
0.006  
0.270  
0.201  
0.007  
0.039  
0.002  
0.010  
0.281  
0.209  
0.012  
D2  
b
e
0.0197 BSC  
0.50 BSC  
L
0.012  
0.008  
0.020  
-
0.30  
0.20  
0.50  
-
k
49  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
64 LEAD LOW-PROFILE QUAD FLAT PACK (10 x 10 x 1.4 mm LQFP)  
REV. 1.0.0  
D
D1  
48  
33  
49  
32  
D1  
D
64  
17  
1
16  
B
A2  
e
C
A
α
Seating Plane  
A1  
L
Note: The control dimension is the millimeter column  
INCHES  
MAX  
MILLIMETERS  
SYMBOL  
MIN  
MIN  
MAX  
1.60  
0.15  
1.45  
0.27  
0.20  
12.20  
10.10  
A
A1  
A2  
B
0.055  
0.002  
0.053  
0.007  
0.004  
0.465  
0.390  
0.063  
0.006  
0.057  
0.011  
0.008  
0.480  
0.398  
1.40  
0.05  
1.35  
0.17  
0.09  
11.80  
9.90  
C
D
D1  
e
0.020 BSC  
0.50 BSC  
L
0.018  
0.030  
0.45  
0.75  
α
0°  
7°  
0°  
7°  
50  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
68 LEAD PLASTIC LEADED CHIP CARRIER (PLCC)  
D
C
Seating Plane  
D1  
45° x H  
1
A2  
45° x H  
2
2 1 68  
B1  
B
D
3
D
2
D
D
1
e
R
D
3
A1  
A
Note: The control dimension is the inch column  
INCHES MILLIMETERS  
SYMBOL  
MIN  
0.165  
0.090  
MAX  
0.200  
0.130  
MIN  
MAX  
5.08  
3.30  
A
4.19  
2.29  
A
A
1
2
0.020  
---.  
0.51  
---  
B
0.013  
0.026  
0.021  
0.032  
0.33  
0.66  
0.53  
0.81  
B
1
C
0.008  
0.985  
0.950  
0.013  
0.995  
0.958  
0.19  
25.02  
24.13  
0.32  
25.27  
24.33  
D
D
1
2
3
D
D
0.890  
0.930  
22.61  
23.62  
0.800 typ.  
0.050 BSC  
0.042  
20.32 typ.  
1.27 BSC  
e
H
H
0.056  
0.048  
0.045  
1.07  
1.07  
0.64  
1.42  
1.22  
1.14  
1
2
0.042  
0.025  
R
51  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
80 LEAD PLASTIC QUAD FLAT PACK (12 mm x 12 mm LQFP, 1.4 mm Form)  
REV. 1.0.0  
Note: The control dimension is the millimeter column  
INCHES  
MAX  
MILLIMETERS  
SYMBOL  
MIN  
MIN  
MAX  
1.60  
0.15  
1.45  
0.27  
0.20  
14.20  
12.20  
A
A1  
A2  
B
0.055  
0.002  
0.053  
0.007  
0.004  
0.543  
0.465  
0.063  
0.006  
0.057  
0.011  
0.008  
0.559  
0.480  
1.40  
0.05  
1.35  
0.17  
0.09  
13.80  
11.80  
C
D
D1  
e
0.0197 BSC  
0.50 BSC  
L
0.018  
0.030  
0.45  
0.75  
α
0°  
7°  
0°  
7°  
52  
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
REVISION HISTORY  
D
ATE  
REVISION  
DESCRIPTION  
August 2007  
May 2008  
Rev P1.0.0 Preliminary Datasheet.  
Rev 1.0.0  
Final Datasheet. Updated DC and AC Electrical Characteristics.  
NOTICE  
EXAR Corporation reserves the right to make changes to the products contained in this publication in order to  
improve design, performance or reliability. EXAR Corporation assumes no responsibility for the use of any  
circuits described herein, conveys no license under any patent or other right, and makes no representation that  
the circuits are free of patent infringement. Charts and schedules contained here in are only for illustration  
purposes and may vary depending upon a user’s specific application. While the information in this publication  
has been carefully checked; no responsibility, however, is assumed for inaccuracies.  
EXAR Corporation does not recommend the use of any of its products in life support applications where the  
failure or malfunction of the product can reasonably be expected to cause failure of the life support system or  
to significantly affect its safety or effectiveness. Products are not authorized for use in such applications unless  
EXAR Corporation receives, in writing, assurances to its satisfaction that: (a) the risk of injury or damage has  
been minimized; (b) the user assumes all such risks; (c) potential liability of EXAR Corporation is adequately  
protected under the circumstances.  
Copyright 2008 EXAR Corporation  
Datasheet May 2008.  
Send your UART technical inquiry with technical details to hotline: uarttechsupport@exar.com.  
Reproduction, in part or whole, without the prior written consent of EXAR Corporation is prohibited.  
53  
XR16M564/564D  
REV. 1.0.0  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
TABLE OF CONTENTS  
GENERAL DESCRIPTION................................................................................................ 1  
F
A
EATURES.................................................................................................................................................... 1  
PPLICATIONS .............................................................................................................................................. 1  
F
F
F
IGURE 1. XR16M564 BLOCK DIAGRAM .......................................................................................................................................... 1  
IGURE 2. PIN  
IGURE 3. PIN  
O
UT  
A
SSIGNMENT  
F
F
OR 68-PIN PLCC PACKAGES  
OR 48-PIN QFN PACKAGE AND 80-PIN LQFP PACKAGE............................................................... 3  
IN 16 AND 68 MODE AND 64-PIN LQFP PACKAGES ......................... 2  
OUT  
ASSIGNMENT  
PIN DESCRIPTIONS ........................................................................................................ 4  
ORDERING INFORMATION ............................................................................................................................... 4  
1.0 PRODUCT DESCRIPTION ...................................................................................................................... 9  
2.0 FUNCTIONAL DESCRIPTIONS ............................................................................................................ 10  
2.1 CPU INTERFACE .............................................................................................................................................. 10  
FIGURE 4. XR16M564 TYPICAL INTEL/MOTOROLA DATA BUS INTERCONNECTIONS.......................................................................... 10  
2.2 DEVICE RESET................................................................................................................................................. 11  
2.3 CHANNEL SELECTION .................................................................................................................................... 11  
TABLE 1: CHANNEL A-D SELECT IN 16 MODE ................................................................................................................................. 11  
TABLE 2: CHANNEL A-D SELECT IN 68 MODE ................................................................................................................................. 11  
2.4 CHANNELS A-D INTERNAL REGISTERS ....................................................................................................... 12  
2.5 INT OUPUTS FOR CHANNELS A-D................................................................................................................. 12  
TABLE 3: INT PIN  
O
PERATION FOR  
T
RANSMITTER FOR  
C
HANNELS A-D ........................................................................................... 12  
TABLE 4: INT PIN  
O
PERATION FOR  
R
ECEIVER FOR  
CHANNELS A-D ................................................................................................. 12  
2.6 DMA MODE ....................................................................................................................................................... 12  
TABLE 5: TXRDY# AND RXRDY# OUTPUTS IN FIFO AND DMA MODE FOR CHANNELS A-D ........................................................... 13  
2.7 CRYSTAL OSCILLATOR OR EXTERNAL CLOCK INPUT.............................................................................. 13  
FIGURE 5. TYPICAL CRYSTAL CONNECTIONS .................................................................................................................................. 13  
2.8 PROGRAMMABLE BAUD RATE GENERATOR WITH FRACTIONAL DIVISOR ........................................... 13  
FIGURE 6. BAUD  
RATE GENERATOR ............................................................................................................................................... 14  
TABLE 6: TYPICAL DATA RATES WITH A 24 MHZ CRYSTAL OR EXTERNAL CLOCK AT 16X SAMPLING ................................................... 15  
2.9 TRANSMITTER.................................................................................................................................................. 15  
2.9.1 TRANSMIT HOLDING REGISTER (THR) - WRITE ONLY........................................................................................... 15  
2.9.2 TRANSMITTER OPERATION IN NON-FIFO MODE.................................................................................................... 16  
F
IGURE 7. TRANSMITTER  
O
PERATION IN NON-FIFO MODE .............................................................................................................. 16  
2.9.3 TRANSMITTER OPERATION IN FIFO MODE ............................................................................................................. 16  
ODE ..................................................................................... 16  
FIGURE 8. TRANSMITTER  
OPERATION IN FIFO AND FLOW CONTROL M  
2.10 RECEIVER....................................................................................................................................................... 17  
2.10.1 RECEIVE HOLDING REGISTER (RHR) - READ-ONLY ............................................................................................ 17  
F
IGURE 9. RECEIVER  
O
O
PERATION IN NON-FIFO MODE.................................................................................................................... 17  
UTO RTS FLOW ODE ....................................................................... 18  
FIGURE 10. RECEIVER  
PERATION IN FIFO AND  
A
CONTROL M  
2.11 AUTO RTS (HARDWARE) FLOW CONTROL................................................................................................ 18  
2.12 AUTO RTS HYSTERESIS ............................................................................................................................... 18  
TABLE 7: AUTO RTS (HARDWARE) FLOW CONTROL ........................................................................................................................ 18  
2.13 AUTO CTS FLOW CONTROL......................................................................................................................... 19  
FIGURE 11. AUTO RTS AND CTS FLOW CONTROL OPERATION....................................................................................................... 19  
2.14 AUTO XON/XOFF (SOFTWARE) FLOW CONTROL...................................................................................... 20  
TABLE 8: AUTO XON/XOFF (SOFTWARE) FLOW CONTROL ............................................................................................................... 20  
2.15 SPECIAL CHARACTER DETECT.................................................................................................................. 20  
2.16 INFRARED MODE ........................................................................................................................................... 21  
FIGURE 12. INFRARED TRANSMIT DATA ENCODING AND RECEIVE DATA DECODING.......................................................................... 21  
2.17 SLEEP MODE WITH AUTO WAKE-UP .......................................................................................................... 22  
2.18 INTERNAL LOOPBACK................................................................................................................................. 22  
FIGURE 13. INTERNAL LOOP BACK IN CHANNELS A - D................................................................................................................... 23  
3.0 UART INTERNAL REGISTERS............................................................................................................. 24  
TABLE 9: UART CHANNEL A AND B UART INTERNAL REGISTERS ..................................................................................... 24  
TABLE 10: INTERNAL REGISTERS DESCRIPTION. SHADED BITS ARE ENABLED WHEN EFR BIT-4=1 ....................................... 25  
4.0 INTERNAL REGISTER DESCRIPTIONS.............................................................................................. 26  
4.1 RECEIVE HOLDING REGISTER (RHR) - READ- ONLY.................................................................................. 26  
4.2 TRANSMIT HOLDING REGISTER (THR) - WRITE-ONLY ............................................................................... 26  
4.3 INTERRUPT ENABLE REGISTER (IER) - READ/WRITE ................................................................................ 26  
4.3.1 IER VERSUS RECEIVE FIFO INTERRUPT MODE OPERATION ............................................................................... 26  
4.3.2 IER VERSUS RECEIVE/TRANSMIT FIFO POLLED MODE OPERATION.................................................................. 27  
1
XR16M564/564D  
1.62V TO 3.63V QUAD UART WITH 32-BYTE FIFO  
REV. 1.0.0  
4.4 INTERRUPT STATUS REGISTER (ISR) - READ-ONLY .................................................................................. 28  
4.4.1 INTERRUPT GENERATION: ........................................................................................................................................ 28  
4.4.2 INTERRUPT CLEARING: ............................................................................................................................................. 28  
TABLE 11: INTERRUPT SOURCE AND PRIORITY LEVEL ..................................................................................................................... 29  
4.5 FIFO CONTROL REGISTER (FCR) - WRITE-ONLY......................................................................................... 29  
TABLE 12: TRANSMIT AND RECEIVE FIFO TRIGGER LEVEL SELECTION ............................................................................................ 30  
4.6 LINE CONTROL REGISTER (LCR) - READ/WRITE......................................................................................... 31  
TABLE 13: PARITY SELECTION ........................................................................................................................................................ 32  
4.7 MODEM CONTROL REGISTER (MCR) OR GENERAL PURPOSE OUTPUTS CONTROL - READ/WRITE.. 32  
TABLE 14: INT OUTPUT MODES ..................................................................................................................................................... 33  
4.8 LINE STATUS REGISTER (LSR) - READ/WRITE ............................................................................................ 34  
4.9 MODEM STATUS REGISTER (MSR) - READ/WRITE...................................................................................... 35  
4.10 SCRATCH PAD REGISTER (SPR) - READ/WRITE ....................................................................................... 35  
4.11 BAUD RATE GENERATOR REGISTERS (DLL AND DLM) - READ/WRITE................................................. 36  
TABLE 15: SAMPLING RATE SELECT ............................................................................................................................................... 36  
4.12 ENHANCED FEATURE REGISTER (EFR) - READ/WRITE ........................................................................... 36  
TABLE 16: SOFTWARE FLOW CONTROL FUNCTIONS ........................................................................................................................ 37  
4.13 SOFTWARE FLOW CONTROL REGISTERS (XOFF1, XOFF2, XON1, XON2) - READ/WRITE................... 38  
TABLE 17: UART RESET CONDITIONS FOR CHANNELS A-D .................................................................................................. 39  
ABSOLUTE MAXIMUM RATINGS.................................................................................. 40  
TYPICAL PACKAGE THERMAL RESISTANCE DATA (MARGIN OF ERROR: ± 15%) 40  
ELECTRICAL CHARACTERISTICS ............................................................................... 40  
DC ELECTRICAL  
AC ELECTRICAL  
TA = -40O TO +85  
C
C
HARACTERISTICS ............................................................................................................. 40  
HARACTERISTICS ............................................................................................................. 41  
C, VCC IS 1.62 TO 3.63V, 70 LOAD WHERE APPLICABLE ........................................... 41  
O
T
PF  
F
F
F
F
F
F
F
F
F
F
F
F
IGURE 14. CLOCK  
IGURE 15. MODEM  
IMING............................................................................................................................................................. 42  
HANNELS A-D .................................................................................................... 43  
HANNELS A-D.................................................................................... 43  
HANNELS A-D.................................................................................. 44  
HANNELS A-D........................................................................... 44  
IMING [NON-FIFO MODE HANNELS A-D ............................................................ 45  
US RITE IMING FOR HANNELS A-D ......................................................................... 45  
EADY & INTERRUPT IMING [NON-FIFO MODE HANNELS A-D .......................................................... 46  
IMING [FIFO MODE, DMA DISABLED  
IMING [FIFO MODE, DMA ENABLED  
I
NPUT/OUTPUT  
T
B
B
IMING  
F
OR  
EAD  
RITE  
US  
C
IGURE 16. 16 MODE (INTEL) DATA  
IGURE 17. 16 MODE (INTEL) DATA  
IGURE 18. 68 MODE (MOTOROLA) DATA  
IGURE 20. RECEIVE EADY & INTERRUPT  
IGURE 19. 68 MODE (MOTOROLA) DATA  
IGURE 21. TRANSMIT  
IGURE 22. RECEIVE  
IGURE 23. RECEIVE  
IGURE 24. TRANSMIT  
IGURE 25. TRANSMIT  
US  
US  
R
W
T
IMING FOR  
IMING FOR  
EAD IMING FOR C  
C
C
T
B
R
T
R
T
] FOR C  
B
W
T
C
R
T
T
T
] FOR C  
READY & INTERRUPT  
]
]
FOR  
FOR  
C
HANNELS A-D........................................... 46  
READY & INTERRUPT  
CHANNELS A-D............................................ 47  
R
R
EADY & INTERRUPT  
EADY & INTERRUPT  
T
T
IMING [FIFO MODE, DMA MODE  
IMING [FIFO MODE, DMA MODE  
D
ISABLED  
]
FOR  
C
HANNELS A-D............................... 47  
E
NABLED  
]
FOR  
CHANNELS A-D ............................... 48  
P
R
ACKAGE  
EVISION  
D
H
IMENSIONS ................................................................................................................................ 49  
ISTORY...................................................................................................................................... 53  
2

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