W83697HF
1.4 Serial Port Interface
SYMBOL
PIN
I/O
IN
FUNCTION
CTSA#
CTSB#
47
55
Clear To Send. It is the modem control input.
The function of these pins can be tested by reading bit 4 of the
handshake status register.
t
DSRA#
DSRB#
48
56
IN
Data Set Ready. An active low signal indicates the modem or data
set is ready to establish a communication link and transfer data to
the UART.
t
49
I/O
UART A Request To Send. An active low signal informs the modem
or data set that the controller is ready to send data.
8t
RTSA#
During power-on reset, this pin is pulled down internally and is
defined as HEFRAS, which provides the power-on value for CR26 bit
6 (HEFRAS). A 4.7 kW is recommended if intends to pull up.
(select 4EH as configuration I/O port¢s address)
HEFRAS
57
50
I/O
UART B Request To Send. An active low signal informs the modem
or data set that the controller is ready to send data.
8t
RTSB#
I/O
UART A Data Terminal Ready. An active low signal informs the
modem or data set that the controller is ready to communicate.
During power-on reset, this pin is pulled down internally and is
8t
DTRA#
PNPCSV#
defined as
, which provides the power-on value for CR24
PNPCSV#
bit 0 ( ). A 4.7 kW is recommended if intends to pull up.
PNPCSV#
(clear the default value of FDC, UARTs, and PRT)
58
I/O
UART B Data Terminal Ready. An active low signal informs the
modem or data set that controller is ready to communicate.
8t
DTRB#
SINA
SINB
51
59
IN
Serial Input. It is used to receive serial data through the
communication link.
t
52
I/O
UART A Serial Output. It is used to transmit serial data out to the
communication link.
8t
SOUTA
During power on reset , this pin is pulled down internally and is
defined as PENROM#, which provides the power on value for CR24
bit 1. A 4.7kW is recommended if intends to pull up .
PENROM#
SOUTB
PEN48
61
I/O
UART B Serial Output. During power-on reset, this pin is pulled
down internally and is defined as PEN48, which provides the power-
on value for CR24 bit 6 (EN48). A 4.7 kW resistor is recommended
if intends to pull up.
8t
DCDA#
DCDB#
53
62
IN
Data Carrier Detect. An active low signal indicates the modem or
data set has detected a data carrier.
t
RIA#
RIB#
54
63
IN
t
Ring Indicator. An active low signal indicates that a ring signal is
being received from the modem or data set.
Publication Release Date:Feb. 2002
- 13 -
Revision 0.70
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