System self-test: Difference between revisions

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= MVS (SP-E VERSION 0) =
= MVS (SP-E VERSION 0) =
[[File:error_cram.jpg|thumb]]
[[File:error_calendar.jpg|thumb]]
[[File:error_vram.jpg|thumb]]
[[File:error_z80.jpg|thumb]]


Here's a tip from a former SNK employee:
Here's a tip from a former SNK employee:

Revision as of 17:12, 28 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)

File:Error cram.jpg
File:Error calendar.jpg
File:Error vram.jpg
File:Error z80.jpg

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)