System self-test: Difference between revisions
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AES and MVS BIOSes compute their own checksums and compare them against the 16bit value at address $000080. The checksum is a simple byte sum of the whole ROM except locations $000080 and $000081. | |||
= AES = | = AES = | ||
Screen color meanings (information by Channelmaniac): | |||
*Blue: All tests passed (The AES does not test the Z80 sound IC). | |||
*Red: [[68k RAM|Work RAM]] error ($100000 region). | |||
*Green: [[Palette RAM]] error ($400000 region). | |||
*Yellow: [[VRAM|Video RAM error]] (programmed through custom port). | |||
*Pink: BIOS selfcheck error (0xC00000 region). | |||
*Cyan: Memory card error (only tested if card in unit and blank). | |||
= MVS (SP-E VERSION 0) = | = MVS (SP-E VERSION 0) = | ||
Here's a tip from a former SNK employee: | |||
Power up the MVS board without a cartridge installed. Look at the border color around the edge of the crosshatch screen. The color will reflect the region the BIOS is for. | |||
Green: 6 slot, an older BIOS | |||
Light Blue: USA BIOS, labeled SPU2 | |||
Dark Blue: Spanish BIOS, labeled SPS2 | |||
Red: Japanese BIOS, labeled SPJ2 | |||
Check order ? | Check order ? | ||
Revision as of 08:46, 23 February 2011
AES and MVS BIOSes compute their own checksums and compare them against the 16bit value at address $000080. The checksum is a simple byte sum of the whole ROM except locations $000080 and $000081.
AES
Screen color meanings (information by Channelmaniac):
- Blue: All tests passed (The AES does not test the Z80 sound IC).
- Red: Work RAM error ($100000 region).
- Green: Palette RAM error ($400000 region).
- Yellow: Video RAM error (programmed through custom port).
- Pink: BIOS selfcheck error (0xC00000 region).
- Cyan: Memory card error (only tested if card in unit and blank).
MVS (SP-E VERSION 0)
Here's a tip from a former SNK employee:
Power up the MVS board without a cartridge installed. Look at the border color around the edge of the crosshatch screen. The color will reflect the region the BIOS is for.
Green: 6 slot, an older BIOS Light Blue: USA BIOS, labeled SPU2 Dark Blue: Spanish BIOS, labeled SPS2 Red: Japanese BIOS, labeled SPJ2
Check order ?
Possible errors:
- WORK RAM ERROR (68k RAM)
- BACKUP RAM ERROR (Battery-backed RAM)
- COLOR RAM BANK0 ERROR (First bank of 256 palettes)
- COLOR RAM BANK1 ERROR (Second bank of 256 palettes)
- VIDEO RAM ERROR (VRAM)
- CALENDAR ERROR
- SYSTEM ROM ERROR (BIOS ROM checksum fail)
- MEMORY CARD ERROR
- Z80 ERROR (no reply to sound command $01)