2.1Main Control Board (BOARD-FFF)

The control board consists of an one chip CPU,a LSI, program/font ROM's, DRAM's, an EEPROM, a host interface circuit, and a mechanism driving circuit.

(1)One-chip CPU

The one-chip CPU is a custom CPU (32-bit internal bus, 32-bit external bus, 120-MHz clock) that incorporates an RISC CPU and its peripheral devices, and has the following functions.

Built-in device

Function

 

 

Chip select controller

Control of peripheral LSI, ROM, DRAM and I/O device

Bus controller

 

DRAM controller

 

 

 

DMA controller

Transfer of data from Host I/F to RAM

 

 

Serial interface controller

Control of RS232C serial interface

 

 

Parallel interface controller

Control of Centronics parallel interface

 

 

Timer

Generation of various control timing

 

Monitoring of paper running and paper size

 

 

Serial I/O port

Control of serial interface between controller and operator panel, EEPROM

 

Control of a serial interface between controller and power supply board

 

 

I/O port

Inputting of various sensor signals

 

Outputting of various control signals

 

 

Motor driver controller

Control of Main Motor

 

 

Image processing circuit

Executes the image data process for printing.

 

 

(2)Program/font ROM's

PCL ROM

The program/font ROM's store the HP LJ5 emulation program and various types of font. MASK ROM is used as the program/font ROM's.

PS ROM

The program/font ROM's store the Adobe PostScript Level 2 program and its fonts.

40930701TH DRAFT Vesion

16 /

Page 16
Image 16
Oki 24DX manual Main Control Board BOARD-FFF, Program/font ROMs, Pcl Rom, Ps Rom