W83977EG-AW Datasheet, PDF (57/142 Pages) Nuvotem Talema – These products are not designed for use in life support appliances

W83977EF-AW/W83977EG-AW
7.2.1 Data Swapper
The system microprocessor can read the contents of the printer's data latch by reading the data
swapper.
7.2.2 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:
7 6 5 4 32 1 0
11
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: Apr. 2006
-55-
Revision 1.2