W83697HF/F
6.2.3 Printer Control Latch and Printer Control Swapper
The system microprocessor can read the contents of the printer control latch by reading the printer
control swapper. Bit definitions are as follows:
7
6
5
4
3
2
1
0
1
1
STROBE
AUTO FD
INIT
SLCT IN
IRQ ENABLE
DIR
Bit 7, 6: These two bits are a logic one during a read. They can be written.
Bit 5: Direction control bit
When this bit is a logic 1, the parallel port is in input mode (read); when it is a logic 0, the parallel
port is in output mode (write). This bit can be read and written. In SPP mode, this bit is invalid
and fixed at zero.
Bit 4: A 1 in this position allows an interrupt to occur when
Bit 3: A 1 in this bit position selects the printer.
changes from low to high.
ACK#
Bit 2: A 0 starts the printer (50 microsecond pulse, minimum).
Bit 1: A 1 causes the printer to line-feed after a line is printed.
Bit 0: A 0.5 microsecond minimum high active pulse clocks data into the printer. Valid data must be
present for a minimum of 0.5 microseconds before and after the strobe pulse.
6.2.4 EPP Address Port
The address port is available only in EPP mode. Bit definitions are as follows:
7
6
5
4
3
2
1
0
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
Publication Release Date: Feb. 2002
Revision 0.70
- 66 -
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