Oki C7200 Service Manual page 27

The engine control block (PU) is controlled by the engine controller board (K71 PWB) which consists of a CPU (MSM66Q577), general LSI chip, flash ROM,
EEPROM, pulse motor drivers and a video memory (see Figure 2-4).
(1) CPU
This, a 16-bit CPU with an AD converter containing 126-Kbyte ROM (OKI MSM66Q577), controls the entire system.
(2) General LSI
This LSI (MG63P011-001LA), which is contained in the printer engine control block, has 4 Mbits of video memory, and functions such as controller-engine video
interfacing, LED interfacing, motor control, sensor input, video memory control, main scan color misalignment correction, skew correction and high voltage power
supply control.
(3) Flash ROM
The flash ROM (29F400-70) is of 4-Mbits, and PU programs are stored in it.
(4) EEPROM
The EEPROM (NM93C66N-NW) is of 4-Kbits, and mounted on the board with an IC socket. Correction values are stored in it.
(5) Pulse Motor Driver
The pulse motor driver (A2919SLBTR, A2918SWV) drives the eight pulse motors to revolve the EP and transport media.
(6) SRAM
This SRAM (62256LFP-7LL) is used as working memory of the CPU.
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