Canon BJC 50 - Color Inkjet Printer Service Manual page 46

Part 2: Product Specifications
8) Input / output signals
COMPATIBILITY MODE
STROBE [Input]:
When the printer receives the STROBE signal low pulse width must be greater than
1.0 µs from the computer, the printer reads the data from the interface and sets the
BUSY signal high.
DATA 1-8 [Input]:
These signals are the 8 bits of parallel data sent from the computer. A high level
indicates a logical 1; a low level indicates a logical 0. The printer reads the DATA
signals when a STROBE signal is received.
ACKNLG [Output]:
The ACKNLG signal tells the computer that the data from the previous STROBE
signal has been read. The computer does not release the next STROBE signal
unless this signal is outputted.
BUSY [Output]:
When the printer sets BUSY signal high, it cannot receive data. The BUSY signal
goes high in response to a STROBE signal. This signal remains high until the data
is read.
BUSY signal is also high when:
Data is received.
Receive buffer is full of data.
A printer error condition such as out-of-paper, paper jamming, etc., has occurred.
P.E. [Output]:
The printer sets Paper End signal high when it determines that it has run out of the
paper or that a paper jam has occurred. PE signal remains high until the operator
loads paper and presses the RESUME button. PE remains unchanged after paper
jamming.
SELECT [Output]:
In BJ mode
When the printer is ready, it sets the SELECT signal high.
In LQ mode
The SELECT signal is always high (pulled up to +5V).
AUTO FEED XT [Input]:
This signal is ignored at all time.
INIT [Input]:
INIT signal from the system resets the printer to its initial power-on state. In BJ
mode, the BUSY signal goes high, and any received data is printed. In LQ mode, the
BUSY signal goes high, and the print buffer is cleared. When INIT signal goes low,
the printer resets to the power-on default state. INIT signal pulse width must be
greater than 50ms from the printer.
The status at start-up is as follows:
Carriage returns to home position.
Function setting reverts back to the initial power-on state.
2-16
BJC-50