Motorola MVME187 User Manual

2-20

Board Level Hardware Description

The PCCchip2 provides an 8-bit bidirectional parallel port. This 
port may be used as a Centronics-compatible parallel printer port 
or as a general parallel I/O port. 

All eight bits of the port must be either inputs or outputs (no 
individual bit selection). 

In addition to the 8 bits of data, there are two control pins and five 
status pins. 

When used as a parallel printer port, these pins function as follows:

Each of the status pins can generate an interrupt to the MPU in any 
of the following programmable conditions: 

❏

High level

❏

Low level

❏

High-to-low transition

❏

Low-to-high transition

Printer Acknowledge (ACK*) 

Printer Fault (FAULT*)

Printer Busy (BSY)

Printer Select (SELECT)

Printer Paper Error (PE)

Printer Strobe (STROBE*)

Input Prime (INP*)