Brother 1250, HL-1030, 1240 service manual Usb I/O

CHAPTER 3 THEORY OF OPERATION

HL-1250

Fig. 3-5 shows the block diagram of the main PCB of the HL-1250 printer.

A S I C

Reset Circuit

Program + Font ROM

4.0 Mbytes

RAM

(4.0 Mbytes)

Option RAM (SIMM)

(max. 32Mbytes)

Option Serial I/O

(RS232C & RS422A)

EEPROM (512 x 8 bits)

CPU Core
(MB86832)
BUS	INT

Oscillator (32.7MHz)

Address Decoder

DRAM Control

Timer

FIFO

CDCC Parallel I/O

USB I/O

Soft Support

EEPROM I/O

Engine Control I/O

To PC

To PC

To Engine PCB

Fig. 3-5

3-5