W83977ATF Datasheet, PDF (191/207 Pages) Winbond – WINBOND I/O

W83977ATF
PRELIMINARY
5.2.3 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 43 21 0
11
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 ACK changes from low to high.
Bit 3: A 1 in this bit position selects the printer.
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.
5.2.4 EPP Address Port
The address port is available only in EPP mode. Bit definitions are as follows:
7 6 5 43 2 1 0
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
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Publication Release Date:April 1998
Revision 0.52