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Service Guide OL400
Chapter 2 Principles of Operation
2.3.02 Operation Panel
The following components make up the operation panel.
4-bit MPU (LC6543C)
LCD control driver (MSM6222B or HD44780)
LCD display (16 characters per line)
Operation panel sheet
LEDs (for online mode indication)
Operation buttons
The LCD control driver (MSM622B or HD44780) converts 4-bit character codes received from the
MPU into 8-bit character codes and retrieves the character pattern data (font) associated with the
8-bit character codes from the internal character generator for display on the LCD.
Operation Panel Interface
The operation panel is controlled by the operation panel interface located on the Main Control
Board via the Engine Board.
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