2–30
Parallel port reg ister bit de finition s (Table 2– 23):
Table 2– 23. Standard and PS/2 Mode Register Bit Definitions
Signal
Name
Full Name
Description
TMOUT Time-out Valid only in EPP mode , this signal goes true
after a 10 µS time-out has occurred on the
EPP bus. This bit is cleared by reset.
ERR* Error Reflects the status of the -ERROR input. 0
means an error has occurred.
SLCT Printer selected
status
Reflects the status of the SLCT input. 1 m eans
a printer is on-line.
PE Paper end Ref lects the s tatus of the PE input. 1 indicates
paper end.
ACK* Acknowledge Reflects the status of the ACK input. 0
indicates a printer received a character..
BUSY* Busy Reflects the complement of the BUSY input. 0
indicates a printer is busy.
STB* Strobe This bit is inverted and output to the -STROBE
pin.
AUTOFD Auto feed This bit is inverted and output to the -AUTOFD
pin.
INIT* Initiate output This bit is output to the -INIT pin.
SELIN* Pr inter selec t
input
This bit is inver ted and output to the pin. It
selects a printer.
IRQE Interrupt request
enable
W hen s et to 1, interrupts are enabled. An
interrupt is generated by the positive-going -
ACK input.
PCD Parallel contr ol
direction
W hen s et to 1, port is in input m ode. In pr inter
mode, the printer is always in output mode
regardless of the state of this bit.
PD0-PD7 Parallel Data Bits