CHAPTER 5 CENTRONICS-COMPATIBLE INTERFACE
This chapter describes the Centronics-compatible interface used es the
I/O
interface to the-M304x series line printer.
5.1 Operation Outline
Basic printer operations which are data transfer, printing, and forms feed, are
shown in Figure 5.1.
Conrrolcode
or FCB command
Data transfer cycle
Forms feed cycle
Figure 5.1 Basic operations
The printer goes online when one of the following conditions occurs (see
Section 5.2 for itnerface signals):
. When the START/STOP switch is pressed:
.
When
control code DC1
(X'll')
and interface signal Data: Strobe are received:
When the printer is online, interface signal Select is set to 1 and the
START/STOP lamp is on. The printer sets the Busy signal to 0 and issues the
Acknowledge signal. In online mode,
the printer receives: i-line print data
sent
from the host, and starts the print cycle when one of the following
conditions occurs:
When the control code (CR, LF,
*
5.3.2): FF, VT, or
DC3)
is received (see Section
. When the FCB command is received (see Section 5.5):
. when the print data buffer
(PDB)
becomes full:
The character code received first is printed in the first print position, the
one received second in the second print position, and so on.
BOZP-1500-OOOlA...05 5-l