w83977atf Winbond Electronics Corp America, w83977atf Datasheet - Page 191

• Manufacturer Part Number: w83977atf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

The system microprocessor can read the contents of the printer control latch by reading the printer
control swapper. Bit definitions are as follows:
Bit 7, 6: These two bits are a logic one during a read. They can be written.
Bit 5: Direction control bit
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
5.2.4 EPP Address Port
The address port is available only in EPP mode. Bit definitions are as follows:
5.2.3 Printer Control Latch and Printer Control Swapper
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.
present for a minimum of 0.5 microseconds before and after the strobe pulse.
1
7
7
6
1
6
5
5
4
3
4
- 87 -
2
3
1
2
0
1
STROBE
AUTO FD
INIT
SLCT IN
IRQ ENABLE
DIR
0
Publication Release Date:April 1998
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
W83977ATF
PRELIMINARY
Revision 0.52