Panasonic JB-3300 Technical Manual page 215

(2) Printer I/O command decoder
This circuit decodes each I/O command when the printer I/O is
selected. Table 5-7 shows printer I/O commands.
Table 5-7
Input
I/O ae I/O Printer I/O Command C mendst al
*PRTCS-1]| XAB1 XABO ommanc signa
0378
ET *
(0 27 8) L L L O S PRINTER DATA STOP
0378 L L L I READ PRINTER DATA *PLBG1L
(0 2 7 8)
0379 L L H I READ PRINTER STATUS *RDPST
(0 2 7 9)
O37 A L H L O SET PRINTER COMMAND *STPCD
(0 2 7 A)
O3 7A
. L H L I READ PRINTER COMMAND *PLBG2
(O 2 7 A)
Note: Either of the I/O addresses 278H - 27FH or 378H - 37FH may be set by
means of a short-circuit plug (J3). When the equipment is shipped,
the I/O address is set to 378H - 37FH.
(3) Data latch and data gate
The data latch latches output data from the CPU to the printer.
The CPU can also read output data by enabling the data gate.
(4) Control signal latch and control signal gate
The control signal latch latches control signals from the CPU to
the printer. The CPU can also read control Signals by enabling
the control signal gate.
(5) Status gate
The CPU reads printer status by enabling the status gate.
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