W83977F Datasheet, PDF (93/181 Pages) Winbond – PLUG & PLAY 1.0A COMPLIANT

W83977F/ W83977AF
Bit 7, 6: These two bits are a logic one during a read. They can be written.
PRELIMINARY
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
The contents of DB0-DB7 are buffered (non-inverting) and output to ports PD0-PD7 during a write
operation. The leading edge of IOW causes an EPP address write cycle to be performed, and the
trailing edge of IOW latches the data for the duration of the EPP write cycle.
PD0-PD7 ports are read during a read operation. The leading edge of IOR causes an EPP address
read cycle to be performed and the data to be output to the host CPU.
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Publication Release Date:March 1998
Revision 0.58