40931201TH Rev. 4 16 /Built-in device FunctionChip select controller Control of peripheral LSI, ROM, DRAM and I/O deviceBus controllerDRAM controllerDMA controller Transfer of data from Host I/F to RAMSerial interface controller Control of RS232C serial interfaceParallel interface controller Control of Centronics parallel interfaceTimer Generation of various control timingMonitoring of paper running and paper sizeSerial I/O port Control of serial interface between controller and operator panel, EEPROMControl of a serial interface between controller and power supply boardI/O port Inputting of various sensor signalsOutputting of various control signalsMotor driver controller Control of Main MotorImage processing circuit Executes the image data process for printing.2.1 Main Control Board (BOARD-FFH)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 CPUThe one-chip CPU is a custom CPU (32-bit internal bus, 32-bit external bus, 140-MHz clock)that incorporates an RISC CPU and its peripheral devices, and has the following functions.(2) Program/font ROM's• PCL ROMThe 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 ROMThe program/font ROM's store the Adobe PostScript Level 2 program and its fonts.
