IO ports
The BJ cartridge rank signals, etc., are input to the IO ports. The power indicator
and error indicator lighting control signals, etc., are output from the output ports.
3) Control ROM (IC3)
The 8Mbit control ROM contains the printer control program.
4) DRAMs (IC5 and IC6)
The 8Mbit DRAMs (4Mbit ×2), which are controlled by the printer controller, are
used as the receive buffer, download buffer, print buffer, and working area.
5) Reset IC (IC8)
The reset IC senses the supply voltage when the power is turned on or when it is
interrupted, and resets the MPU and printer controller.
6) EEPROM (IC7)
The 2Kbit EEPROM, which is controlled by the printer controller, stores the various
printer settings, total waste ink amount, page count, print head removal/
installation count, and resume count, etc.
7) Paper feed motor driver (IC14)
The paper feed motor driver, which is controlled by the MPU, performs constant
current bipolar drive of the paper feed motor, which is controlled using 2-phase
excitation. There are two drive circuits in the IC.
8) Carriage motor driver (IC13)
The carriage motor driver, which is controlled by the MPU, performs constant
current bipolar drive of the carriage motor, which is controlled using double 1-2-
phase excitation.
The carriage motor switches the peak current among 5 steps according to the
switching signals from the MPU to maintain optimum carriage motor drive. There is
one drive circuit in the IC.
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BJC-7100
Part 4: Technical Reference
