W83637HF Datasheet, PDF (22/149 Pages) Winbond – LPC I/O

W83637HF
5.4 Serial Port Interface
SYMBOL PIN
I/O
CTSA#
CTSB#
49
IN_t
78
DSRA#
DSRB#
RTSA#
50
IN_t
79
51
O_8c
HEFRAS
INcd
RTSB#
80
O_8c
ENGMTO
INcd
DTRA
52
O_8c
PNPCVS
INcd
FUNCTION
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.
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.
UART A Request To Send. An active low signal informs the
modem or data set that the controller is ready to send data.
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 kΩ is recommended if intends to pull up.
(select 4EH as configuration I/O port′s address)
UART B Request To Send. An active low signal informs the
modem or data set that the controller is ready to send data.
Watch Dog Time-Out enable.
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
defined as _PNPCVS, which provides the power-on value for CR24
bit 0 (PNPCVS). A 4.7 kΩ is recommended if intends to pull up.
(clear the default value of FDC, UARTs, PRT, Game port and
MIDI port)
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Publication Release Date: June 25, 2003
Revision 1.3