Chapter 22-472.4.2 Main Controller2.4.2.1 Main controller components 0017-4858F-2-46a) ASIC (IC1/IC2)The ASIC with a 16-bit internal bus is driven in sync with the 66 MHz external clock. It supports the following functions:Image processing unitThis unit converts the RGB multi-value image data or CMYK multi-value data received from the host computer through the interface connector to the binary imagedata for the ink colors used.DMA controllerThis controller control DMA transfer of the data transferred through the input interfaces such as the USB and expansion card slot as well as DMA transfer of thedata stored in the DIMM.Image data generation/output functionThis function generates image data for color printing from the received image data and the mask pattern (corresponding to print mode) stored in the FLASH ROM,and stored the generated image data in DIMM. It also outputs the generated image data to the carriage PCB.Interrupt controllerThis controller receives and processes internal interrupts and external interrupts from the USB, image processing unit, and expansion card slot.Timer functionEven when the printer is turned off, the timer function is held on using the RTC(IC803) and lithium battery(BAT801) to assist the cleaning function.When the power cord is plugged to the outlet, power is supplied to the RTC and therefore the lithium battery power is not consumed.Heat Enable signal control functionThis function uses the pulse width to perform variable control of the time of application of the Heat Enable signal to the nozzle heater board for each printheadnozzle array.Linear scale count functionThis function reads the linear scale when the carriage moves, thus generating the ink discharge timing. It also counts the linear scale timing cycle using the referenceclock to measure the carriage moving speed.Dot count functionThis function controls the discharge dots used as the information for Heat Enable signal control, maintenance jet control, cleaning control, and remaining ink levelfor each nozzle array.Operation panel control functionThis function controls serial communication with the operation panel.PWM control functionThis function controls driving of the suction fan and mist fan as well as the temperature of the printhead.Remaining ink level detection functionThis function detects the remaining level of each color of ink based on the signal received from the hollow needle mounted in the ink tank unit.LED control functionThis function controls the LEDs on the ink tank unit.I/O port functionThis function controls input signals from sensors.Power ON/OFF control functionThis function controls turning on/off of the drive power (26 V and 21.5 V) supplied from the power supply PCB.Head DI sensor read control functionIC3101IC2801IC2901IC3001IC701IC302 IC301 BAT801IC803IC3101IC2IC2801IC3901IC3901IC2901IC3001IC802IC701IC601IC1IC602IC603IC604IC302 IC301IC1201BAT801