W83977F Datasheet, PDF (20/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
PRELIMINARY
1.2 Advanced Power Management, continued
SYMBOL PIN
I/O
FUNCTION
PANSW
73
IN_t CR2B bit7, 6=00 (default): On/Off switch for Advanced Power
Management (APM). This signal indicates a request to switch
the power on or off. When the VDD of the chip is disrupted, a
high to low transition on this pin indicates a switch on request.
When VDD returns, a high to low transition on this pin indicates a
switch off request.
GP23 (P15)
I/O_12t
CR2B bit7, 6=01: General purpose I/O port 2, bit 3. It can be
configured as Keyboard P15 I/O port.
DCDC
IN_t CR2B bit7, 6=11: DCD input of UART C. [W83977AF only]
1.3 Serial Port Interface
SYMBOL PIN
I/O
CTSA
CTSB
41
IN_t
48
DSRA
DSRB
RTSA
42
IN_t
49
43
I/O_8t
HEFRAS
RTSB
nPENPLL
50
I/O_8t
DTRA
PNPCSV
44
I/O_8t
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 kΩ 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)
Publication Release Date: March 1998
-9 -
Revision 0.58