8XC198

Symbol

Name and Function

Port 2

Multi-functional port All of its pins are shared with other functions in the 80C198

Ports 3 and 4

8-bit bidirectional IO ports with open drain outputs These pins are shared with

the multiplexed addressdata bus which has strong internal pullups Available as

IO only on the ROM and EPROM devices

TxD

The TxD pin is used for serial port transmission in Modes 1 2 and 3 In mode 0 the

pin is used as the serial clock output

RxD

Serial Port Receive pin used for serial port reception In mode 0 the pin functions

as input or output data

EXTINT

A positive transition on the EXTINT pin will generate an external interrupt

T2CLK

The T2CLK pin is the Timer2 clock input or the serial port baud rate generator

input

T2RST

A rising edge on the T2RST pin will reset Timer2

PWM

The PWM output

PMODE

Programming Mode Select Determines the EPROM programming algorithm that is

performed PMODE is sampled after a chip reset and should be static while the

part is operating

SID

Slave ID Number Used to assign each slave a pin of Port 3 or 4 to use for passing

programming verification acknowledgement

PALE

Programming ALE Input Accepted by the 87C196KB when it is in Slave

Programming Mode Used to indicate that Ports 3 and 4 contain a command

address

PROG

Programming Falling edge indicates valid data on PBUS and the beginning of

programming Rising edge indicates end of programming

PVAL

Program Valid This signal indicates the success or failure of programming in the

Auto Programming Mode A zero indicates successful programming

PVER

Program Verification Used in Slave Programming and Auto CLB Programming

Modes Signal is low after rising edge of PROG if the programming was not

successful

AINC

Auto Increment Active low signal indicates that the auto increment mode is

enabled Auto Increment will allow reading or writing of sequential EPROM

locations without address transactions across the PBUS for each read or write

PORTS 3 and 4

AddressCommandData Bus Used to pass commands addresses and data to

and from slave mode 87C196KBs Used by chips in Auto Programming Mode to

(when programming)

pass command addresses and data to slaves Also used in the Auto Programming

Mode as a regular system bus to access external memory Should have pullups to

6