Brother HL-3450CN Service Manual page 103

CHAPTER 4 STRUCTURE OF SYSTEM COMPONENTS
Fig.4-38 shows the timing of each signal after the power switch is turned on.
Power On
IREADY-N
PRREQ-N
VSYNC-N
VIDEO-P
VSYNC-N
15us MIN.
10ms MAX.
HSYNC-N
VIDEO-P
The COMMAND signal and STATUS signal are the signals that are used to transfer the data
between the controller and the engine, which perform as a half-duplex asynchronous serial
communication. Refer to Fig.4-39.
NOTE:
x Based on "Asynchronous Communication" method.
x Command/Status communication must keep the "Handshake Rule".
x Baud rate is 9600 bps.
x Frame format: - one (1) start bit,
x The video controller has to send an "Initialize Command" to the engine controller after
power on in order to establish communication.
The power for the Main PCB is supplied through the engine interface connector.
210s MAX.
0.1sec. MIN.
15sec. MAX.
(K) data
417.781us
1st line
6WDUW ELW
LSB
- eight (8) data bits
(Start bit side is LSB, Parity bit is MSB),
- one (1) odd parity bit,
- one (1) stop bit.
(C) data (M) data
2nd line
Fig. 4-38
6WRS ELW
3DULW\ ELW
P
8ms (TYP)
MSB
6WDUW ELW
Fig. 4-39
4-50
1.0sec. MAX.
3.75s 3.0sec. MAX. for Continuous Printing
(Y) data
56.296ns
1dot Last line
30ms (MAX)
LSB
MSB
P
3DULW\ ELW
6WRS ELW