W83977F-A Datasheet, PDF (17/182 Pages) Winbond – WINBOND I/O

W83977F-A/ W83977G-A/ W83977AF-A/ W83977AG-A
Advanced Power Management, continued.
SYMBOL PIN
I/O
FUNCTION
GP23 (P15)
I/O12t
CR2B bit7, 6=01: General purpose I/O port 2, bit 3. It can be configured
as Keyboard P15 I/O port.
DCDC
INt
CR2B bit7, 6=11: DCD input of UART C. [W83977AF only]
4.3 Serial Port Interface
SYMBOL PIN
I/O
CTSA
CTSB
41
INt
48
DSRA
DSRB
RTSA
42
INt
49
43
I/O8t
HEFRAS
RTSB
nPENPLL
50
I/O8t
DTRA
PNPCSV
44
I/O8t
DTRB
ENCPNP
51
I/O8t
SINA
SINB
45, 52
INt
FUNCTION
Clear To Send 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 370H
as configuration I/O port address)
UART B 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 nPENPLL, which provides the power-on value for CR24 bit 5 (ENPLL)
and bit 6. A 4.7 k Ω is recommended if intends to pull up. (PLL is
disabled)
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 PNPCSV , which provides the power-on value for CR24 bit 0
( PNPCSV ). A 4.7 kΩ is recommended if intends to pull up. (clear the
default value of FDC, UARTs, and PTR)
UART B Data Terminal Ready. An active low signal informs the modem
or data set that controller is ready to communicate.
During power-on reset, this pin is pulled down internally and is defined
as ENCPNP, which provides the power-on value for CR24 bit 1
(ENPNP). A 4.7 k Ω is recommended if intends to pull up. (enable
comply PnP mode)
Serial Input. Used to receive serial data through the communication link.
Publication Release Date: May 2006
-9 -
Revision 0.60