Instruction manual

Table Of Contents
PC215E Page 26
5.3.2 Programmable Peripheral Interface PPI-X Data Register Port B
This eight bit register writes to and reads from port B of the 82C55 Programmable Peripheral
Interface PPI-X. All input/output lines PB0 to PB7 of this device are available to the user on
connector SK1 as digital I/O.
Register
Offset
Write and/or
Read
Register
Width
Register
Title
Mnemonic
01
16
Write and Read 8 bits
82C55 Programmable Peripheral
Interface X Port B Data Register
PPI-X B
FUNCTION
The PPI-X Port B Data Register is used to write or read 8 bit data to a port of the 82C55
Programmable Peripheral Interface device.
The PPI can be configured to operate in several modes. Further details may be found by
reference to the device manufacturer's 82C55 data sheets in the appendices.
The eight data bits of port B are data input or data output in all modes
The modes and programming of PPI operations are outlined in chapters 4 and 6 with the Digital
I/O connections shown in chapter 3.
BIT ASSIGNMENTS
The bit layout of the PPI-X port B data register is shown below.
01234567
PPI-X Port B Digital
I/O Data Bits
Digital I/O SK1
Pin Connections
SK1 46
SK1 7
SK1 65
SK1 26
SK1 45
SK1 6
SK1 64
SK1 25
PB0
PB1
PB2
PB3
PB4
PB5
PB6
PB7