Logic Section Components - Canon BJC-8500 Service Manual

Part 4: Technical Reference

4.2.2 Logic section components

1) MPU (IC1)
The MPU contains a 16-bit CPU, 24-bit address bus, 512-byte work RAM and 9
peripheral I/O ports (interrupt controller, DMAC, timer, I/O ports, A/D converter,
DRAM controller, chip select controller, monitor timer, clock and power manager).
Built-in CPU
32-bit wide general-purpose registers are built into the 16-bit CPU. This CPU
operates in synchronization with a 16 MHz external clock input.
Address bus
24-bit address bus port is connected to the printer controller.
Data bus
The 16-bit data bus port for external devices is connected to the 8 Mbit control ROM
and printer controller.
Built-in RAM
512-byte RAM is accessed in 16-bit units.
Interrupt controller
34 internal interrupt causes and 9 external interrupt causes are input to the MPU,
and interrupt processing is carried out on each of these causes.
DMA (Direct Memory Access) controller
This MPU has four built-in DMA controllers supporting 16 Mbyte space.
Timer/timing pattern controller/monitoring timer
Five built-in 16-bit integrated timer units are connected to the timing pattern
controller and carriage motor driver. The timing pattern controller outputs carriage
motor PWM signals, and 2-phase excitation drive signals for the paper feed motor
and purge motor.
I/O port
The I/O ports are connected to switches on the panel board, etc.
A/D converter
Detects the following analog signals via the built-in A/D converter:
AN0: Detects the head rank in BJ cartridge.
AN1: Detects the Black head/Photo head temperature from the head temperature
sensor in BJ cartridge.
AN2: Detects the Color head temperature from the head temperature sensor in BJ
cartridge.
AN3: Unused
AN4: Unused
AN5: Detects ink-out.
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