Canon MultiPASS C755 Service Manual page 138

d) Printer control section
d-1) MPU&Printer controller (IC 101)
The main functions of the printer controller are as follows:
• Bi-centronics interface
• EEP-ROM control
• DRAM control
• Buffer control
• Print head control
Also, the printer controller include MPU function are as follows:
• 16 bit CPU
• 21 bit address bus
• 16 bit data bus
• Carriage motor/Paper feed motor control
The stepping motor controller outputs the carriage motor's single- and two-phase exciter drive signal,
and paper feed motor's two-phase drive signal.
The stepping motor controller switches the carriage motor with the 5-step peak current value for
optimum driving. The stepping motor controller outputs the switching control signal to the carriage
motor driver.
• Detection of BJ head temperature
• Detection of printer's internal temperature.
• Detection of Home position sensor, Paper edge sensor and Pickup roller sensor.
• Cartridge detection.
d-2) ROM (IC 202)
The 8 Mbit control/CG ROM contains the program and bitmap font data for printer control.
d-3) DRAM (IC 102)
16 Mbit DRAM is used as the print buffer, and working area.
d-4) EEPROM (IC 301)
Controlled by the printer controller, the 2 Kbit EEPROM (Electrically Erasable and Programmable
ROM) stores various printer emulation settings, and the waste ink amount discharged to the waste ink
absorber.
MultiPASS C755 Chapter 3: Maintenance & Service
3-87