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3.3.3 Main PCB (Video Controller PCB)
[ 1 ] Outline
The main PCB consists of the circuits which perform the following functions;
• Receive the printing data from the computer.
• Convert the received data to the bitmap data such as characters or graphics.
• Control the engine and send the generated bitmap data as a video signal.
The control panel is controlled by communicating with the engine CPU to display LCD messages,
light the LEDs and display the button status, etc.
The power for the main PCB is supplied from the engine through the engine interface connector.
[ 2 ] Circuit
(1) CPU
• Model name: VR5500, core
MIPS 64bit RISC CPU manufactured by NEC
• Clock speed: 89MHz (external) / 266MHz (internal)
• Cache memory: 32KB (Command cache) / 32KB (Data cache)
• Bus width: 32bit (external) / 64bit (internal)
Internal Floating Point Unit (FPU)
(2) ASIC block
• Model name: PD800268F1 manufactured by NEC
• Appearance: 316pin BGA
• Functions:
* Controls CPU
* Controls memory
* Controls interrupts
* Timer
* External interfaces (Centronics, PCI, IDE, Compact Flash, USB)
* Engine interface (Video signal control, LVDS)
* Supports Software
(3) ROM block
The ROM stores the CPU control program and font data. ROMs used are an 16Mbytes flash
ROM, and an 8 Mbytes flash ROM which can be rewritten on the board.
<Masked ROM>
• Model name: S29GL128N90TFIR20H
• Access time: less than 90nsec.
• Appearance: 56pin TSOP
<Flash ROM>
• Model name: S29GL064M90TCIR20 manufactured by SPANSION
• Access time: less than 90nsec.
• Appearance: 48-pin TSOP
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