Canon MultiPASS C50 Service Manual page 233

Timing chart
The parallel interface transfers data in one direction only: from computer to printer. The data path is 8
bits wide. The printer and the computer synchronize data transfer with the interface signals, -STROBE, -
ACKNLG, and BUSY.
When the computer is ready to send a byte of data to the printer, it puts the byte of data on the data lines
(DATA 1 through DATA 8). Then the computer sends a -STROBE pulse to the printer. The printer
responds with a BUSY signal.
When the printer receives the data, it pulses the -ACKNLG line. This signals the computer that the
printer has read the byte of data into the printer memory. If the printer buffer is not full and it can receive
more data, it removes the BUSY signal.
The timing charts that follow illustrate the data and handshake lines during the transfer of one data byte
from the computer. DATA 1 through DATA 8 and the -STROBE line are driven by the computer; the -
ACKNLG line is driven by the printer.
0.5 µs 0.5 µs0.5 µs
BJ mode
MIN. MIN.
DATA 1-8
-STROBE
BUSY
-ACKNLG
0.5 µs 0.5 µs 0.5 µs
Epson LQ mode
MIN. MIN. MIN.
DATA 1-8
-STROBE
BUSY
-ACKNLG
MIN.
Approx 6.0 µs
Approx 3.0 µs
Figure 1-3 Interface Timing
1-9
Chapter 1: General Description
µs
Approx 3.0