W83877 Winbond Electronics Corp America, W83877 Datasheet - Page 54

• Manufacturer Part Number: W83877
• Description: Winbond I/O
• Manufacturer: Winbond Electronics Corp America

5.2 Enhanced Parallel Port (EPP)
TABLE 5-2 PRINTER MODE AND EPP REGISTER ADDRESS
Notes:
1. These registers are available in all modes.
2. These registers are available only in EPP mode.
5.2.1 Data Swapper
The system microprocessor can read the contents of the printer's data latch by reading the data
swapper.
5.2.2 Printer Status Buffer
The system microprocessor can read the printer status by reading the address of the printer status
buffer. The bit definitions are as follows:
Bit 7: This signal is active during data entry, when the printer is off-line during printing, when the print
busy
Bit 6: This bit represents the current state of the printer's ACK signal. A 0 means the printer has
Bit 5: A 1 means the printer has detected the end of paper.
Bit 4: A 1 means the printer is selected.
Bit 3: A 0 means the printer has encountered an error condition.
A2
0
0
0
0
0
1
1
1
1
head is changing position, or during an error state. When this signal is active, the printer is
received a character and is ready to accept another. Normally, this signal will be active for
and cannot accept data.
approximately 5 microseconds before BUSY stops.
A1
0
0
1
1
1
0
0
1
1
A0
0
1
0
0
1
0
1
0
1
7
6
Data port (R/W)
Printer status buffer (Read)
Printer control latch (Write)
Printer control swapper (Read)
EPP address port (R/W)
EPP data port 0 (R/W)
EPP data port 1 (R/W)
EPP data port 2 (R/W)
EPP data port 2 (R/W)
5
4
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3
1
2
1
1
REGISTER
0
TMOUT
ERROR
SLCT
PE
ACK
BUSY
W83877F
NOTE
1
1
1
1
2
2
2
2
2