Difference between revisions of "Sega Mega Drive/Hardware revisions"
From Sega Retro
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{{SectionsNew | {{SectionsNew | ||
| name=VA0 (JPN) | | name=VA0 (JPN) | ||
− | | image= | + | | image=Mega_Drive_JPN_VA0.png |
| desc=Components: | | desc=Components: | ||
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Due to a last-minute issue 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 master oscillator (53.6931 MHz, NTSC), a 74LS74 (dual D-type flip-flops), and two 74LS161s (4-bit counter). | Due to a last-minute issue 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 master oscillator (53.6931 MHz, NTSC), a 74LS74 (dual D-type flip-flops), and two 74LS161s (4-bit counter). | ||
+ | |||
+ | An issue in the hardware causes the RAM memory to not completely initialize when the game starts, causing crashes in [[Osomatsu-kun Hachamecha Gekijou]]. | ||
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{{SectionsNew | {{SectionsNew | ||
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| image=Genesis_1_VA_3_Serial_No_-_31X21232.jpg | | image=Genesis_1_VA_3_Serial_No_-_31X21232.jpg | ||
| desc=Components: | | desc=Components: | ||
− | *M68K CPU: Motorola | + | *M68K CPU: Motorola MC68000P8 |
*M68K memory: 2x HM65256BL-10 (32Kx8 PSRAM, 100 ns) | *M68K memory: 2x HM65256BL-10 (32Kx8 PSRAM, 100 ns) | ||
*Z80 CPU: Zilog Z0840004PSC | *Z80 CPU: Zilog Z0840004PSC | ||
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{{SectionsNew | {{SectionsNew | ||
| name=VA4 (JPN) | | name=VA4 (JPN) | ||
− | | image= | + | | image=SegaMegadriveVA4Board.jpg |
− | | desc= | + | | desc=Components: |
+ | *M68K CPU: Signetics SCN68000C8N64 | ||
+ | *M68K memory: 2x TC51832SP-12 | ||
+ | *Z80 CPU: Zilog Z0840004PSC | ||
+ | *Z80 memory: NEC D4168C-15-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 | ||
}} | }} | ||
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{{SectionsNew | {{SectionsNew | ||
| name=VA6 (JPN) | | name=VA6 (JPN) | ||
− | | image= | + | | image=Mega Drive PCB IC BD M5 VA6.jpg |
− | | desc= | + | | desc=The first Japanese revision with the [[TradeMark Security System|TMSS]]. |
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
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{{SectionsNew | {{SectionsNew | ||
| name=VA6.8 | | name=VA6.8 | ||
− | | image= | + | | image=Model_v6.8.jpg |
| desc= | | desc= | ||
}} | }} | ||
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*Main ASIC: Sega 315-5660 | *Main ASIC: Sega 315-5660 | ||
*Video Encoder: Fujitsu MB3514 | *Video Encoder: Fujitsu MB3514 | ||
+ | *Amplifier: BA10324AF | ||
+ | }} | ||
+ | {{SectionsNew | ||
+ | | name=VA1.8 (USA) | ||
+ | | image=Genesis_2_PCB_VA1.8_serail_040169192.jpg | ||
+ | | desc=PCB Printed by SKS | ||
+ | Components: | ||
+ | *M68K CPU: Motorola MC68HC000FN8 | ||
+ | *M68K memory: [[Sanyo]] LC36648ML-10 | ||
+ | *Z80 CPU: Toshiba 84C00AU-6 | ||
+ | *Main ASIC: Sega 315-5660-02 | ||
+ | *Video Encoder: Samsung KA2195D | ||
*Amplifier: BA10324AF | *Amplifier: BA10324AF | ||
}} | }} | ||
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| name=VA1.8 (USA) | | name=VA1.8 (USA) | ||
| image=PC_BD_MD2_VA1.8_USA.JPG | | image=PC_BD_MD2_VA1.8_USA.JPG | ||
− | | desc=Components: | + | | desc=PCB Printed by CMK |
+ | Components: | ||
*M68K CPU: Motorola MC68HC000FN8 | *M68K CPU: Motorola MC68HC000FN8 | ||
*M68K memory: [[Sanyo]] LC331632M-12 | *M68K memory: [[Sanyo]] LC331632M-12 | ||
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| name=VA1 (USA) | | name=VA1 (USA) | ||
| image=PC BD MD3 VA1 USA.jpg | | image=PC BD MD3 VA1 USA.jpg | ||
− | | desc= | + | | desc=Components: |
+ | *IC1: Sega 315-5960 ASIC (see above) | ||
+ | *IC2: Sharp LH5P1632N-15 32Kx16 PSRAM | ||
+ | *IC5: OKI M54C864-80 512K (64K x 8-bit) VRAM | ||
+ | *IC6: Sony CXA1645M RGB Encoder | ||
+ | *IC7: TI LM324 amplifier | ||
+ | IC3 and IC4 markings are silkscreened but don't correspond to any physical ICs. | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew |
Revision as of 22:12, 2 February 2022
- Back to: Sega Mega Drive.
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Model 1
VA0 (JPN) | |
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Components:
Due to a last-minute issue 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 master oscillator (53.6931 MHz, NTSC), a 74LS74 (dual D-type flip-flops), and two 74LS161s (4-bit counter). An issue in the hardware causes the RAM memory to not completely initialize when the game starts, causing crashes in Osomatsu-kun Hachamecha Gekijou. | |
VA1 (JPN) | |
Components:
| |
VA2 (USA, High Definition Graphics) | |
Components:
| |
VA3 (USA, High Definition Graphics) | |
Components:
| |
VA4 (JPN) | |
Components:
| |
VA4 (PAL) | |
Components:
| |
VA5 (JPN) | |
VA6 (JPN) | |
The first Japanese revision with the TMSS. | |
VA6 (USA, High Definition Graphics) | |
Components:
| |
VA6 (PAL) | |
VA6.8 | |
VA7 (USA) | |
Model 2
VA0 (JPN) | |
---|---|
VA0 (PAL) | |
VA0 (USA) | |
Components:
| |
VA1 (USA) | |
VA1 (PAL) | |
Components:
| |
VA1.8 (USA) | |
PCB Printed by SKS
Components:
| |
VA1.8 (USA) | |
PCB Printed by CMK
Components:
| |
VA1.8 (PAL) | |
Components:
| |
VA1.8 (Asia) | |
Components:
| |
VA2 (USA) | |
VA2.3 (USA) | |
VA3 | |
VA4 | |
Components:
This is the first Mega Drive board without any 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. |