w83977ctf Winbond Electronics Corp America, w83977ctf Datasheet - Page 75

• Manufacturer Part Number: w83977ctf
• Description: Winbond I/o
• Manufacturer: Winbond Electronics Corp America

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:
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
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:
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.
7
1
7
6
1
6
5
5
4
3
4
-66 -
2
3
1
2
0
ACK#
1
STROBE
AUTO FD
INIT#
SLCT IN
IRQ ENABLE
DIR
0
changes from low to high.
Publication Release Date: March 1999
PD0
PD1
PD2
PD3
PD4
PD5
PD6
PD7
W83977EF/ CTF
PRELIMINARY
Revision A1