Difference between revisions of "Sega Mega Drive/Hardware revisions"
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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]]. | + | An issue in the hardware causes the RAM memory to not completely initialize when the game starts, causing crashes in ''[[Osomatsu-kun Hachamecha Gekijou]]''. |
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| Line 64: | Line 64: | ||
*Z80 CPU: Zilog Z0840004PSC | *Z80 CPU: Zilog Z0840004PSC | ||
*Z80 memory: KM6264BL-10 (8Kx8 SRAM, 100 ns) | *Z80 memory: KM6264BL-10 (8Kx8 SRAM, 100 ns) | ||
| − | *I/O chips: Sega 315- | + | *I/O chips: Sega 315-5309, Sega 315-5364 |
*VDP: Sega 315-5313 (Yamaha YM7101) | *VDP: Sega 315-5313 (Yamaha YM7101) | ||
*Video RAM: KM424C64Z-10, VKF015 (64Kx4 VRAM) | *Video RAM: KM424C64Z-10, VKF015 (64Kx4 VRAM) | ||
| Line 110: | Line 110: | ||
| name=VA6 (JPN) | | name=VA6 (JPN) | ||
| image=Mega Drive PCB IC BD M5 VA6.jpg | | image=Mega Drive PCB IC BD M5 VA6.jpg | ||
| − | | desc= | + | | desc=The first Japanese revision with the [[TradeMark Security System|TMSS]]. |
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| Line 128: | Line 128: | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| − | | name=VA6 (PAL) | + | | name=VA6.5 (PAL) |
| image=MD1_IC_BD_M5_PAL_VA6.jpg | | image=MD1_IC_BD_M5_PAL_VA6.jpg | ||
| − | | desc= | + | | desc=The unused female DE-9 port (used for the [[Mega Modem]] in Japan) is removed. |
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| Line 140: | Line 140: | ||
| name=VA7 (USA) | | name=VA7 (USA) | ||
| image=PC BD M5 USA VA7.jpg | | image=PC BD M5 USA VA7.jpg | ||
| − | | desc= | + | | desc=Components: |
| + | *M68K CPU: Motorola MC68HC000FN8 | ||
| + | *M68K memory: 2x 65256BLFP-10T | ||
| + | *Z80 CPU: Zilog Z0840004PSC | ||
| + | *Main ASIC: Sega 315-5487-01 | ||
| + | *Headphone amp: BA10324AF | ||
| + | *Video encoder: Sony CXA1145M | ||
| + | *FM synthesizer: Yamaha YM2612 (ASIC YM3438) | ||
| + | |||
| + | This revision is similar to the VA0 revision of the Model 2, in which it has a different M68K CPU and memory chips, as well as the main ASIC and audio amplifiers. The only difference is the Z80 CPU, which is in the same design used with the rest of the Model 1 revisions. | ||
| + | |||
| + | A function on the VDP (integrated into the ASIC) has broken PAL 50Hz support. | ||
}} | }} | ||
|} | |} | ||
| Line 149: | Line 160: | ||
| name=VA0 (JPN) | | name=VA0 (JPN) | ||
| image=MD2 JAPAN PCB VA0 UP.jpg | | image=MD2 JAPAN PCB VA0 UP.jpg | ||
| − | | desc= | + | | desc=The YM2612 is now based on the YM3438, and is integrated into the main ASIC (the Sega 315-5487-10). |
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| Line 227: | Line 238: | ||
*Z80 memory: [NUMBER PLEASE] (8Kx8 SRAM) | *Z80 memory: [NUMBER PLEASE] (8Kx8 SRAM) | ||
*Main ASIC: Sega 315-5660 | *Main ASIC: Sega 315-5660 | ||
| + | *Amplifier: BA10324AF | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| name=VA2 (USA) | | name=VA2 (USA) | ||
| image=PC BD MD2 VA2 USA.jpg | | image=PC BD MD2 VA2 USA.jpg | ||
| − | | desc= | + | | desc=Components: |
| + | *M68K CPU: Motorola MC68HC000FN12 | ||
| + | *M68K memory: Sanyo LC331632M-12 | ||
| + | *Z80 CPU: Zilog Z84C0006FEC | ||
| + | *Main ASIC: Sega 315-5786 | ||
| + | *Amplifier: Sega 315-5684 | ||
| + | *FM synthesizer: Yamaha YM2612 | ||
| + | |||
| + | This revision (along with the VA2.3) is the only Model 2 boards with a discrete YM2612 chip. | ||
| + | |||
| + | Additional circuitry is present on the daughterboard located on the PCB, with model number 171-6961A. | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| name=VA2.3 (USA) | | name=VA2.3 (USA) | ||
| image=PC BD MD2 VA2.3 USA.jpg | | image=PC BD MD2 VA2.3 USA.jpg | ||
| − | | desc= | + | | desc=Components: |
| + | *M68K CPU: Motorola MC68HC000FN12 | ||
| + | *M68K memory: Toshiba TC511632FL-10 (32Kx16 PSRAM, 100 ns) | ||
| + | *Z80 CPU: Zilog Z84C0006FEC | ||
| + | *Z80 memory: KM78128LG-7 (8Kx8 SRAM) | ||
| + | *Main ASIC: Sega 315-5685 | ||
| + | *Video Encoder: Sony CXA1645M | ||
| + | *Amplifier: Sega 315-5684 | ||
| + | *FM synthesizer: Yamaha YM2612 | ||
| + | |||
| + | This revision (along with the VA2) is the only Model 2 boards with a discrete YM2612 chip. | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| name=VA3 | | name=VA3 | ||
| image=PC_BD_MD2_VA3_USA_HAL.JPG | | image=PC_BD_MD2_VA3_USA_HAL.JPG | ||
| − | | desc= | + | | desc=Components: |
| + | *M68K CPU: Motorola MC68HC000FN12 | ||
| + | *M68K memory: ??? 651632DFP-15 | ||
| + | *Z80 CPU: Zilog Z84C0006FEC | ||
| + | *Main ASIC: Sega 315-5660 | ||
| + | *Video Encoder: Sony CXA1645M | ||
| + | *Amplifier: Sega 315-5684 | ||
}} | }} | ||
{{SectionsNew | {{SectionsNew | ||
| Line 253: | Line 291: | ||
*IC5: Sony CXA1645M video encoder | *IC5: Sony CXA1645M video encoder | ||
*IC6: 7805 voltage regulator | *IC6: 7805 voltage regulator | ||
| − | 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, | + | 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, YM3438, and I/O controllers. |
}} | }} | ||
|} | |} | ||
| Line 264: | Line 302: | ||
| desc=Components: | | desc=Components: | ||
*IC1: Sega 315-5960 ASIC (see above) | *IC1: Sega 315-5960 ASIC (see above) | ||
| − | *IC2: Sharp | + | *IC2: Sharp LH5P1632N-15 32Kx16 PSRAM |
*IC5: OKI M54C864-80 512K (64K x 8-bit) VRAM | *IC5: OKI M54C864-80 512K (64K x 8-bit) VRAM | ||
*IC6: Sony CXA1645M RGB Encoder | *IC6: Sony CXA1645M RGB Encoder | ||
| Line 274: | Line 312: | ||
| image=PC_BD_MD3_VA2_USA.jpg | | image=PC_BD_MD3_VA2_USA.jpg | ||
| desc=Components: | | desc=Components: | ||
| − | *Main ASIC: Sega 315-6123 (contains M68K, Z80, VDP, | + | *Main ASIC: Sega 315-6123 (contains M68K, Z80, VDP, YM3438, and probably some other components.) |
*Memory (right of main ASIC): NEC D4502161G5 (128Kx16 SDRAM) | *Memory (right of main ASIC): NEC D4502161G5 (128Kx16 SDRAM) | ||
*Oscillator (bottom-right of main ASIC): SG53 PTR S 53.6931M | *Oscillator (bottom-right of main ASIC): SG53 PTR S 53.6931M | ||
*Video Encoder (bottom-left of main ASIC): Sony CXA1645M | *Video Encoder (bottom-left of main ASIC): Sony CXA1645M | ||
*Amplifier (left of main ASIC): TI 85AFTRF LM324 | *Amplifier (left of main ASIC): TI 85AFTRF LM324 | ||
| + | |||
| + | The <tt>tas</tt> function of the M68K (which was broken in prior revisions) has been fixed in this revision, making some games such as ''[[Gargoyles]]'' unplayable. | ||
}} | }} | ||
|} | |} | ||
[[Category:Mega Drive hardware]] | [[Category:Mega Drive hardware]] | ||
Latest revision as of 13:47, 4 December 2023
- Back to: Sega Mega Drive.
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Model 1
|
VA0 (JPN) |
|---|---|
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. | |
.JPG)
|
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:
| |
|
VA6.5 (PAL) |
| The unused female DE-9 port (used for the Mega Modem in Japan) is removed. | |
|
VA6.8 |
|
VA7 (USA) |
Components:
This revision is similar to the VA0 revision of the Model 2, in which it has a different M68K CPU and memory chips, as well as the main ASIC and audio amplifiers. The only difference is the Z80 CPU, which is in the same design used with the rest of the Model 1 revisions. A function on the VDP (integrated into the ASIC) has broken PAL 50Hz support. |
Model 2
|
VA0 (JPN) |
|---|---|
| The YM2612 is now based on the YM3438, and is integrated into the main ASIC (the Sega 315-5487-10). | |
|
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) |
Components:
This revision (along with the VA2.3) is the only Model 2 boards with a discrete YM2612 chip. Additional circuitry is present on the daughterboard located on the PCB, with model number 171-6961A. | |
|
VA2.3 (USA) |
Components:
This revision (along with the VA2) is the only Model 2 boards with a discrete YM2612 chip. | |
|
VA3 |
Components:
| |
|
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, YM3438, and I/O controllers. |
Model 3
|
VA1 (USA) |
|---|---|
Components:
IC3 and IC4 markings are silkscreened but don't correspond to any physical ICs. | |
|
VA2 (USA) |
Components:
The tas function of the M68K (which was broken in prior revisions) has been fixed in this revision, making some games such as Gargoyles unplayable. |