T. Harman and D. Hein, the Motorola Mc68000 Microprocessor Family , Prentice-hall, 2nd Edition, 1996

Back to: Sega Mega Drive.

This commodity needs cleanup. This article needs to exist edited to suit to a higher standard of article quality. Afterwards the article has been cleaned up, yous may remove this message. For help, see the How to Edit a Page article.

Model 1

	VA0 (JPN)
	Components: M68K CPU: Signetics SCN68000C8N64 M68K retention: 2x HM65256BLSP-fifteen (32Kx8 PSRAM, 150 ns) Z80 CPU: Zilog Z0840004PSC Z80 memory: TMM2063P - ten (8Kx8 SRAM, 100 ns) I/O chips: Sega 315-5308, Sega 315-5309, Signectic 74LS00N, 74LS161AN, 74F161AN, 74LS74AN (DIP-16) VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: 2x HM53461ZP-12 (64Kx4 VRAM 120 ns) Headphone amp: Sony CXA1034 Video encoder: Sony CXA1145 FM synthesizer: Yamaha YM2612 Due to a last-minute consequence with the VDP in H40 mode, additional clock circuitry had to be added during manufacturing. This circuitry is present on a daughterboard in the center of the PCB, and contains the chief oscillator (53.6931 MHz, NTSC), a 74LS74 (dual D-type flip-flops), and two 74LS161s (four-bit counter). An effect in the hardware causes the RAM memory to non completely initialize when the game starts, causing crashes in Osomatsu-kun Hachamecha Gekijou.
	VA1 (JPN)
	Components: M68K CPU: Signetics SCN68000C8N64 M68K memory: 2x TC51832SPL-10 (32Kx8 PSRAM, 100 ns) Z80 CPU: Zilog Z0840004PSC Z80 memory: NEC D4168C-20 (8Kx8 XRAM, 200 ns) I/O chips: Sega 315-5308, Sega 315-5309, Sega 315-5339 (DIP-16) VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: 2x HM53461ZP-12 (64Kx4 VRAM 120 ns) Headphone amp: Sony CXA1034 Video encoder: Sony CXA1145 FM synthesizer: Yamaha YM2612 Capacitors : TK Japan
	VA2 (USA, High Definition Graphics)
	Components: M68K CPU: Signetics SCN68000C8N64 M68K retentiveness: 2x TC51832SPL-12 (32Kx8 PSRAM, 120 ns) Z80 CPU: Zilog Z0840004PSC Z80 memory: NEC D4168C-15 (8Kx8 XRAM, 150 ns) I/O fries: Sega 315-5308, Sega 315-5309, Sega 315-5345 (DIP-sixteen) VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: 2x [NUMBER PLEASE] (64Kx4 VRAM) Headphone amp: Sony CXA1034 Video encoder: Sony CXA1145 FM synthesizer: Yamaha YM2612
	VA3 (USA, Loftier Definition Graphics)
	Components: M68K CPU: Motorola MC68000P8 M68K memory: 2x HM65256BL-10 (32Kx8 PSRAM, 100 ns) Z80 CPU: Zilog Z0840004PSC Z80 retention: KM6264BL-x (8Kx8 SRAM, 100 ns) I/O chips: Sega 315-5308, Sega 315-5309 VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: KM424C64Z-10, VKF015 (64Kx4 VRAM) Headphone amp: Sony CXA1034 Video encoder: Sony CXA1145 FM synthesizer: Yamaha YM2612 Capacitors : Taicon, Chhsi
	VA4 (JPN)
	Components: M68K CPU: Signetics SCN68000C8N64 M68K retention: 2x TC51832SP-12 Z80 CPU: Zilog Z0840004PSC Z80 memory: NEC D4168C-fifteen-SG I/O chips: Sega 315-5364, Sega 315-5309 VDP: Sega 315-5313 (Yamaha YM7101) Headphone amp: Sony CXA1034P Video encoder: Sony CXA1145P FM synthesizer: Yamaha YM2612
	VA4 (PAL)
	Components: M68K CPU: Motorola MC68000P8 M68K memory: Hitachi HM65256BLSP-ten (32Kx8 PSRAM, 100 ns) I/O chip: Sega 315-5364, Sega 315-5309 Z80 CPU: Zilog Z0840004PSC Z80 retentivity: Sanyo LC3664RL (8Kx8 SRAM, 120 ns) VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: Fujitsu MB81461-12 (64Kx4 VRAM) Headphone amp: Sony CXA1034P Video encoder: Sony CXA1145P RGB Encoder FM synthesizer: Yamaha YM2612 Dual Operational Amplifier: Ti LM358P
	VA5 (JPN)
	VA6 (JPN)
	The get-go Japanese revision with the TMSS.
	VA6 (The states, High Definition Graphics)
	Components: M68K CPU: Motorola MC68000P8 M68K memory: 2x HM652568LSP-ten (32Kx8 PSRAM, 100 ns) Z80 CPU: Zilog Z0840004PSC Z80 memory: MB8464A-ten (8Kx8 SRAM, 100 ns) I/O chip: Sega 315-5433 VDP: Sega 315-5313 (Yamaha YM7101) Video RAM: 2x [NUMBER PLEASE] (64Kx4 DRAM) Headphone amp: Sony CXA1034 Video encoder: Sony CXA1145P FM synthesizer: Yamaha YM2612
	VA6 (PAL)
	VA6.eight
	VA7 (USA)

Model 2

	VA0 (JPN)
	VA0 (PAL)
	VA0 (USA)
	Components: M68K CPU: Hitachi HD68HC000CP8 M68K retentivity: Toshiba TC51832AFL-10 Z80 CPU: Toshiba 84C00AU-vi Main ASIC: Sega 315-5487-01 Video Encoder: Samsung KA2195D Amplifier: Texas Instruments 311223J
	VA1 (USA)
	VA1 (PAL)
	Components: M68K CPU: Motorola MC68HC000FN8 M68K memory: Sanyo LC331632M-12 Z80 CPU: Toshiba 84C00AU-6 Main ASIC: Sega 315-5660 Video Encoder: Fujitsu MB3514 Amplifier: BA10324AF
	VA1.eight (U.s.)
	PCB Printed by SKS Components: M68K CPU: Motorola MC68HC000FN8 M68K retentiveness: Sanyo LC36648ML-10 Z80 CPU: Toshiba 84C00AU-6 Main ASIC: Sega 315-5660-02 Video Encoder: Samsung KA2195D Amplifier: BA10324AF
	VA1.8 (USA)
	PCB Printed past CMK Components: M68K CPU: Motorola MC68HC000FN8 M68K memory: Sanyo LC331632M-12 Z80 CPU: Zilog Z84C0006FEC Main ASIC: Sega 315-5660 Video Encoder: Samsung KA2195D Amplifier: BA10324AF
	VA1.8 (PAL)
	Components: M68K CPU: Motorola MC68HC000FN8 M68K retention: ??? 651632DFP-xv Z80 CPU: Zilog Z84C0006FEC Chief ASIC: Sega 315-5660 Video Encoder: Fujitsu MB3514 Amplifier: BA10324AF
	VA1.8 (Asia)
	Components: M68K CPU: Motorola MC68HC000FN8 M68K memory: Toshiba TC511632FL-x (32Kx16 PSRAM, 100 ns) Z80 CPU: Toshiba 84C00AU-6 Z80 retentiveness: [NUMBER Please] (8Kx8 SRAM) Chief ASIC: Sega 315-5660
	VA2 (USA)
	VA2.3 (Usa)
	VA3
	VA4
	Components: IC1: Sega 315-5960 ASIC IC2: 32Kx16 PSRAM IC3: Video RAM? IC4: Sega 315-5684 sound amplifier IC5: Sony CXA1645M video encoder IC6: 7805 voltage regulator This is the first Mega Drive board without whatever discrete CPUs. Both the 68000 and Z80 are contained with the Sega 315-5960 ASIC, as well as the VDP, YM2612, and I/O controllers.

Model 3

	VA1 (USA)
	Components: IC1: Sega 315-5960 ASIC (see above) IC2: Precipitous LH5P1632N-15 32Kx16 PSRAM IC5: OKI M54C864-80 512K (64K 10 viii-bit) VRAM IC6: Sony CXA1645M RGB Encoder IC7: TI LM324 amplifier IC3 and IC4 markings are silkscreened but don't correspond to whatsoever physical ICs.
	VA2 (Usa)
	Components: Main ASIC: Sega 315-6123 (contains M68K, Z80, VDP, YM2612, and probably some other components.) Retentivity (right of principal ASIC): NEC D4502161G5 (128Kx16 SDRAM) Oscillator (bottom-correct of main ASIC): SG53 PTR S 53.6931M Video Encoder (bottom-left of main ASIC): Sony CXA1645M Amplifier (left of principal ASIC): TI 85AFTRF LM324

barnhartdide1956.blogspot.com

Source: https://segaretro.org/Sega_Mega_Drive/Hardware_revisions

Share this post