Programming Model

Printer Data Register

ADR/SIZ

 

$FFF4203A (16-bits)

 

 

 

BIT

 

15-0

 

 

 

NAME

 

PD15 - PD0

 

 

 

OPER

 

R/W

 

 

 

RESET

 

X

 

 

 

 

PD15-PD0

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.

3

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Motorola MVME1X7P manual Printer Data Register