
W83877ATF
Publication Release Date: April 1998
- 8 -
Version 0.51
1.2 Serial Port Interface, continued
SYMBOL
PIN
I/O
FUNCTION
RIB
50
IN
t
Ring Indicator. An active low indicates that a ring signal is being
received by the modem or data set.
A15
IN
t
System address bus bit 15, when 16-bit address decoder is
selected.
SINA
30
IN
t
Serial Input of COM A. Used to receive serial data from the
communication link.
SINB
42
IN
t
Serial Input of COM B. Used to receive serial data from the
communication link.
IRRX1
IN
t
When infrared function is selected, acts as infrared input.
SOUTA
38
I/O
8tc
UART A Serial Output. Used to transmit serial data out to the
communication link.
PEN16SA
IN
t
During power-on reset, this pin is pulled up internally and is
defined as PEN16SA, which provides the power-on value for
CR2E.bit6
(
PEN16SA
). A 4.7 k
is recommended when
intending to pull down at power-on reset.
SOUTB
43
I/O
12t
UART B Serial Output. Used to transmit serial data out to the
communication link.
IRTX1
IN
t
Infrared serial data output when COM B acts as infrared port.
DTRA
35
I/O
8tc
UART A Data Terminal Ready. An active low informs the
modem or data set that the controller is ready to communicate.
PHEFRAS
IN
t
During power-on reset, this pin is pulled down internally and is
defined as PHEFRAS, which provides the power-on value for
CR16 bit 0 (HEFRAS), and Configuration Port is defined at 250h.
A 4.7 k
is recommended when intending to pull up at power-on
reset, and Configuration Port is defined at 3F0h.
DTRB
46
I/O
8t
UART B Data Terminal Ready. An active low informs the
modem or data set that controller is ready to communicate.
RTSA
36
I/O
8tc
UART A Request To Send. An active low informs the modem or
data set that the controller is ready to send data.
PPNPCVS
IN
t
During power-on reset, this pin is pulled up internally and is
defined as PPNPCVS, which provides the power-on value for
CR16 bit 2 (PNPCVS). A 4.7 k
is recommended when
intending to pull down at power-on reset.