Star Micronics TSP400 Printer User Manual


 
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THEORY OF OPERATION
Parallel Interface PCB Main PCB
DATA 1
DATA 2
DARA 3
DATA 4
DATA 5
DARA 6
DATA 7
DATA 8
STROBE
BUSY
ACK
ERROR
SELECTED
PAPER OUT
A4
B4
A5
B5
A6
B6
A7
B7
A13
A12
B12
A10
A11
B11
CN3
CPU
CN1
IC5
CN9
A4
B4
A5
B5
A6
B6
A7
B7
A13
A12
B12
A10
A11
B11
Gate array
IC10
LS05
IC1
CD0
CD1
CD2
CD3
CD4
CD5
CD6
CD7
CSTB
BUSY
ACK
ERROR
SELECT
POUT
2-1-3. Parallel interface
Fig. 2-4 Parallel Interface
The host computer sends eight bits of parallel data to CN3 when the printer is ready (when BUSY is LOW).
The data passes through the interface PCB and gate array, then moves into the CPU.
Printer signals from the CPU (ACK, ERROR, SELECTED, PAPER OUT, etc.) pass through the gate array and are output
over the appropriate connector pins.