W83977TF-A View Datasheet(PDF) - Winbond

Part Name

Description

Manufacturer

W83977TF-A

WINBOND I/O

Winbond 

1.3 Serial Port Interface

SYMBOL PIN

I/O

CTSA

CTSB

41

INt

48

DSRA

DSRB

RTSA

42

INt

49

43

I/O8t

HEFRAS

RTSB

50

I/O8t

DTRA

44

I/O8t

PNPCSV

DTRB

SINA

SINB

SOUTA

51

I/O8t

45, 52

46

INt

I/O8t

PENKBC

SOUTB

PEN48

DCDA

DCDB

53

I/O8t

47

INt

54

W83977TF

PRELIMINARY

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′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.

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 PRT)

UART B Data Terminal Ready. An active low signal informs the

modem or data set that controller is ready to communicate.

Serial Input. Used to receive serial data through the

communication link.

UART A Serial Output. Used to transmit serial data out to the

communication link.

During power-on reset, this pin is pulled down internally and is

defined as PENKBC, which provides the power-on value for CR24

bit 2 (ENKBC). A 4.7 kΩ resistor is recommended if intends to pull

up. (enable KBC)

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 kΩ resistor is

recommended if intends to pull up.

Data Carrier Detect. An active low signal indicates the modem or

data set has detected a data carrier.

Publication Release Date: April 1998

-8-

Revision 0.62

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