Canon BJC-8500 Service Manual

Also see for BJC-8500: User manual

Contents

2) Printer controller (IC2)The printer controller contains the CPU interface controller, DRAM controller, SRAMcontroller, parallel/serial interface controller, print head controller, data processingcontroller and I/O port controller.CPU interface controllerThe CPU interface controller controls read/write from the CPU.DRAM controllerThe DRAM controller is a DRAM-specific bus independent of the MPU bus. Itcontrols the 32 Mbit DRAM (16 Mbit DRAM × 2), 10-bit address/32-bit data bus,and executes read/write control, RAS/CAS control, and refresh control.SRAM controllerThe SRAM controller is an SRAM-specific bus independent of the MPU bus. Itcontrols the 256 Kbit SRAM, the 15-bit address/8-bit data bus, and executesread/write control.Parallel/serial interface controllerThe parallel interface controller functions to receive the 8-bit parallel data thatarrives from the host computer synchronized with the strobe (STROBE) signal byhandshaking the BUSY and ACKNLG signals. This controller also controls serialinterface signals.The data received over the parallel and serial interfaces is stored in the DRAM'sreceive buffer, is parsed by the MPU and is processed by DMA (direct memoryaccess) if the MPU judges the data to be print data.Print head controllerThis controller performs two simultaneous operations, serial transfer of print dataread from the DRAM's print buffer to the print heads, and output of the blocksignals and heat enable signals to drive the print heads.With transfer of print data, print data for each of the print heads is transferredsynchronized with the 8 MHz clock CLK signal. With print head drive, block signalsData 1 and Data 2 and the pulse signals (HE and SHE) are output.Data processing controllerThis controller processes print data in the DRAM's print buffer by DMA (directmemory access). Processing includes palette conversion for printing out photos,1200 dpi smoothing and vertical-horizontal conversion for preparing raster-directionprint data to column-direction print data.I/O portSignals from the sensors are input to the input port. Signals for controlling lightingof the POWER and ERROR indicators are output from the output port.4-39BJC-8500Part 4: Technical Reference