Printer Data Register - Motorola MVME1X7P Programmer's Reference Manual

Printer Data Register

ADR/SIZ
BIT
NAME
OPER
RESET
PD15-PD0
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$FFF4203A (16-bits)
15-0
PD15 - PD0
R/W
X
Writing to these bits causes the PCCchip2 to latch data
into the external printer data buffer. Generally the printer
data buffer only connects to PD7-PD0, because most
printer data paths are 8 bits wide.
PD7-PD0 can be accessed as an 8-bit register at location
$FFF4203B, or PD15-PD0 can be accessed as a 16-bit
register at location $FFF4203A.
In auto mode, writing these bits also generates the strobe
for the printer. Reading these bits causes the PCCchip2 to
read the data from the printer data signal lines (no strobe
is generated).
When the DOEN bit is set, the printer data signal lines are
driven by the external printer data buffer. When the
DOEN bit is cleared, they must be terminated to high or to
low and/or an external device must drive them.
Programming Model
3-47
3