Table of Contents
Advertisement
CP 521
5
Principle of Operation and Addressing
This section describes how the CPU monitors the data traffic of the CP 521 and
how the printer output module is addressed.
5.1
Monitoring of the CP 521 by the CPU
Every data interchange between the CP 521 and the CPU must be started by the
CPU sending a job to the CP 521. The CPU controls the operations of the CP 521 as
follows:
•
Print mode:
In print mode, the CP 521 outputs messages to a printer autonomously when
instructed to do so by the CPU. The program continues to run independently
of message text output. The CPU receives data from the CP 521 on the status
of the CP 521 and the printer. In addition, the CP 521 tells the CPU if it can
handle the jobs requested by the CPU.
•
ASCII mode:
In this mode, the CP 521 enables the exchange of data between the CPU and a
peripheral device. The CPU reads data from the CP 521 into the PII and
instructs the CP 521 to pass on data to a terminal device (terminal, keyboard,
etc.) or to another CP 521.
GWA 4NEB 812 6030-02b
Principle of Operation and Addressing
5-1
Advertisement
Chapters
Table of Contents
