User's Guide
Interfaces C-3
Printer Error Signals
The printer uses two signals to notify the computer of printer errors:
PAPER and ERROR-. PAPER goes high and ERROR- goes low when
the printer has data to print but is out of paper. ERROR- also goes low
when the printer is off-line or in an error state. PAPER returns low and
ERROR- returns high when the error is corrected.
Printer Control Signals
The computer uses two signals to control certain printer operations: AUTO
FEED- and IPRIME-. With AUTO FEED- low, the printer advances the
paper one line after printing; with AUTO FEED- high or disconnected, no
action occurs. When IPRIME- pulses low for at least 50 microseconds,
the printer initializes printer settings to the defaults and clears the input
buffer; with IPRIME- high or disconnected, no action occurs.
Printer Select Signals
The computer uses a SELIN- signal to select the printer to receive data.
The printer uses a SELOUT signal to tell the computer that it is selected
and ready to receive data. For the printer's parallel interface to operate,
SELIN- must be low or disconnected. SELOUT remains high as long as
SELIN- is low or disconnected.
Figure C-1. Parallel Data Transfer Timing Diagram
STROBE-
DATA
BUSY
ACK-
0.5 µs minimum
0.5 µs
min.
0.5 µs minimum
0.25 µs maximum
4 µs minimum
(or when printer buffer can hold more data)
5 µs minimum
User's Guide
Interfaces C-3
Printer Error Signals
The printer uses two signals to notify the computer of printer errors:
PAPER and ERROR-. PAPER goes high and ERROR- goes low when
the printer has data to print but is out of paper. ERROR- also goes low
when the printer is off-line or in an error state. PAPER returns low and
ERROR- returns high when the error is corrected.
Printer Control Signals
The computer uses two signals to control certain printer operations: AUTO
FEED- and IPRIME-. With AUTO FEED- low, the printer advances the
paper one line after printing; with AUTO FEED- high or disconnected, no
action occurs. When IPRIME- pulses low for at least 50 microseconds,
the printer initializes printer settings to the defaults and clears the input
buffer; with IPRIME- high or disconnected, no action occurs.
Printer Select Signals
The computer uses a SELIN- signal to select the printer to receive data.
The printer uses a SELOUT signal to tell the computer that it is selected
and ready to receive data. For the printer's parallel interface to operate,
SELIN- must be low or disconnected. SELOUT remains high as long as
SELIN- is low or disconnected.
Figure C-1. Parallel Data Transfer Timing Diagram
STROBE-
DATA
BUSY
ACK-
0.5 µs minimum
0.5 µs
min.
0.5 µs minimum
0.25 µs maximum
4 µs minimum
(or when printer buffer can hold more data)
5 µs minimum