Main Pcb Block Diagram - Brother HL-1440 Service Manual

CHAPTER 3 THEORY OF OPERATION
1.2

Main PCB Block Diagram

HL-1230/1440
Fig. 3-4 shows the block diagram of the main PCB of the HL-1230/1440 printer.
Reset Circuit
Program + Font ROM
1.0 Mbytes
RAM
(2.0 Mbytes)
Option RAM (SIMM)
(max.32Mbytes)
(HL-1440 only)
EEPROM (128
CPU Core
(MB86833)
BUS
8 bits)
To Engine PCB
Oscillator (33.33MHz)
INT
Address Decoder
CDCC Parallel I/O
USB I/O (HL-1440 only)
Engine Control I/O
Fig. 3-4
3-4
A S I C
DRAM Control
Timer
FIFO
Soft Support
EEPROM I/O
To PC
To PC