W83977A Winbond Electronics Corp America, W83977A Datasheet - Page 60

• Manufacturer Part Number: W83977A
• Description: Winbond I/O
• Manufacturer: Winbond Electronics Corp America

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
Bit 6: This bit represents the current state of the printer's ACK signal. A 0 means the printer has
Bit 5: Logical 1 means the printer has detected the end of paper.
Bit 4: Logical 1 means the printer is selected.
Bit 3: Logical 0 means the printer has encountered an error condition.
Bit 1, 2: These two bits are not implemented and are logic one during a read of the status register.
Bit 0: This bit is valid in EPP mode only. It indicates that a 10 S time-out has occurred on the EPP
head is changing position, or during an error state. When this signal is active, the printer is
busy and cannot accept data.
received a character and is ready to accept another. Normally, this signal will be active for
approximately 5 microseconds before BUSY stops.
bus. A logic 0 means that no time-out error has occurred; a logic 1 means that a time-out error
has been detected. Writing a logic 1 to this bit will clear the time-out status bit; writing a logic 0
has no effect.
7
6
5
4
- 51 -
3
1
2
1
1
0
TMOUT
ERROR
SLCT
PE
ACK
BUSY
Publication Release Date: March 1998
W83977TF
PRELIMINARY
Revision 0.62