Brother International HL-3400CN Service Manual - Page 101

CHAPTER 4 STRUCTURE OF SYSTEM COMPONENTS Fig.4-38 shows the timing of each signal after the power switch is turned on. Power On I READY-N PRREQ-N VSYNC-N VIDEO-P 210s MAX. 0.1sec. MIN. 15sec. MAX. (K) data (C) data 1.0sec. MAX. 3.75s 3.0sec. MAX. for Continuous Printing (M) data Y data VSYNC-N HSYNC-N VIDEO-P 15us MIN. 10ms MAX. 417 781us 1st line 2nd line S p 296ns 1dot I Last line Fig. 4-38 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. COMMAND Start bit LSB Stop bit Parity bit \11 MSB 8ms (TYP) 30ms (MAX) STATUS LSB MSB Fig. 4-39 Start bit Parity bit Stop bit NOTE: • Based on "Asynchronous Communication" method. • Command/Status communication must keep the "Handshake Rule". • Baud rate is 9600 bps. • Frame format: - one (1) start bit, - eight (8) data bits (Start bit side is LSB, Parity bit is MSB), - one (1) odd parity bit, - one (1) stop bit. • 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. 4-50