Instruction manual

AMPDIO DRIVERS
Page 66
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 on the SOFTMAN CD.
The eight data bits of port A are data input, data output or bi-directional data I/O according to the
PPI mode:
Mode 0 Input or Output
Mode 1 Input or Output
Mode 2 Bi-directional Input/output
BIT ASSIGNMENTS
The bit layout of the PPI-X Port A data register is shown below.
7 6 5 4 3 2 1 0
PPI-X Port A Digital
I/O Data Bits
SK1 3
SK1 61
SK1 22
SK1 41
SK1 2
SK1 60
SK1 21
SK1 40
Digital I/O SK1
Pin Connections
PA0
PA1
PA2
PA3
PA4
PA5
PA6
PA7
5.4.1.2 82C55 Programmable Peripheral Interface PPI Data Register Port B
This eight-bit register writes to and reads from port B of the 82C55 Programmable Peripheral
Interface PPI.
Register
Offset
Write and/or
Read
Register
Width
Register
Title
Mnemonic
01
16
Write and Read 8 bits
82C55 Programmable
Peripheral Interface Port B
Data Register
PPI B
FUNCTION
The PPI 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 on the SOFTMAN CD.
The eight data bits of port B are data input or data output in all modes