W83977F-A Datasheet, PDF (91/182 Pages) Winbond – WINBOND I/O

W83977F-A/ W83977G-A/ W83977AF-A/ W83977AG-A
8.2.2 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:
76
54
32 1
11
0
TMOUT
ERROR
SLCT
PE
ACK
BUSY
Bit 7: This signal is active during data entry, when the printer is off-line during printing, when the print
head is changing position, or during an error state. When this signal is active, the printer is busy
and cannot accept data.
Bit 6: This bit represents the current state of the printer's ACK signal. A 0 means the printer has
received a character and is ready to accept another. Normally, this signal will be active for
approximately 5 microseconds before BUSY stops.
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 μS time-out has occurred on the EPP
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.
Publication Release Date: May 2006
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Revision 0.60