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1.2 Video Controller Circuit
(1) CPU block
CPU(#26) IDT79R3041-20J manufactured by Integrated Device Technology
RISC chip
Clock speed: 19.6608 MHz
Appearance: 84-pin PLCC
(2) ASIC/Gate Array Block
• #32 M65243FP(Mitsubishi) - 208-pin QFP
Controls the address decoder, timers and interfaces (Centronics and RS-232C).
• #6 M65340FP(Mitsubishi) 80-pin QFP
Controls HRC(High Resolution Control), GSC(Gray Scale Control) and economy mode.
• #3 µPD65626GF-176-3BA(NEC) - 100-pin QFP
Controls the I/O ports and others.
(3) Font Cartridge/Card Block
• Font cartridge (option)
The font cartridge has a 32MB memory area and is controlled by the 16-bit bus.
The address bus a buffer LS244 and the data bus, a buffer LS245.
• Font Card (option)
The font card has a 32MB memory area and is controlled by the 16-bit bus.
The card is supplied with 12V power because the flash card requires 12V power supply when
writing or erasing data.
The address bus is buffered by LS244 and the data bus, is buffered by LS245.
(4) Centronics/RS-232C interface block
• Centronics parallel interface
Data transmission and reception are controlled by the M65243FP (#32).
• RS-232C
Data transmission and reception are controlled by the M65243FP (#32).
The ADM202JRN (#38) serves as driver/receiver.
(5) SIMM block
• SIMM (Single-Inline-Memory-Module) allows memory extension up to 26MB
• 3 SIMM sockets are available.
• SIMM should be of 72-pin type and its access time should be less than 70 ns.
• 4 types of SIMM (1MB, 2MB, 4MB and 8MB) can be combined:
1MB MH25632BJ-7 (MITSUBISHI), HB56D25632B-7A (HITACHI)
2MB MH51232BJ-7 (MITSUBISHI), HB56D51232B-7A (HITACHI)
4MB MH1M32EJ-7 (MITSUBISHI), HB56A132BT-7A (HITACHI)
8MB MH2M32EJ-7 (MITSUBISHI), HB56A232BT-7A (HITACHI)
1) The SIMMs have its printed marking on the PCB by silk screen: SLOT1, SLOT2 and
SLOT3, respectively. The SIMMs should be set in the order of SLOT1 - SLOT3.
2) SIMMs should be set in the order of its memory size and in the order of SLOT No.
Example: 3 SIMMs: 1MB, 2MB and 4MB
SLOT1 - 4MB
SLOT2 - 2MB
SLOT3 - 1MB