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.
Todo: Order of checks.


= AES =
=Cartridge systems=


Screen color meanings (information by Channelmaniac):
Some 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) =
The AES home console only performs checks when no game is detected.


Here's a tip from a former SNK employee:
{|class="regdef"
|'''Error'''
|No game
|[[WORK RAM ERROR]]
|[[COLOR RAM ERROR]]
|[[VIDEO RAM ERROR]]
|[[SYSTEM ROM ERROR]]
|[[MEMORY CARD ERROR]]
|-
|'''AES'''
|[[File:aes_sc_blue.png]]
|[[File:aes_sc_red.png]]
|[[File:aes_sc_green.png]]
|[[File:aes_sc_yellow.png]]
|[[File:aes_sc_pink.png]]
|[[File:aes_sc_cyan.png]]
|-
|'''MVS'''
|[[File:crosshatch.png|160px]] [[Crosshatch]]
|[[File:error_wram.png|160px]]
|[[File:error_color0.png|160px]]
|[[File:error_vram.png|160px]]
|[[File:error_sysrom.png|160px]]
|Screenshot needed
|-
|'''Meaning'''
|All tests passed (AES does not test the {{Chipname|Z80}}). Cartridge not detected.
|[[68k user RAM]] R/W error
|[[Palette RAM]] R/W error
|[[VRAM]] R/W error
|[[system ROM error|System ROM checksum mismatch]]
|[[Memory card]] R/W error (only tested if card present and blank)
|}


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.
==MVS checks==


Green: 6 slot, an older BIOS
Additionnal checks are performed on MVS systems. The SP-S2 [[system ROM]] does them in the following order:
Light Blue: USA BIOS, labeled SPU2
Dark Blue: Spanish BIOS, labeled SPS2
Red: Japanese BIOS, labeled SPJ2


Check order ?
# Work RAM
# Backup RAM
# Palette RAM bank 0
# Palette RAM bank 1
# Low VRAM
# High VRAM
# RTC
# System ROM checksum
# Z80


Possible errors:
{|class="regdef"
*WORK RAM ERROR (68k RAM)
|'''Error'''
*BACKUP RAM ERROR (Battery-backed RAM)
|[[BACKUP RAM ERROR]]
*COLOR RAM BANK0 ERROR (First bank of 256 palettes)
|[[Calendar freeze]]
*COLOR RAM BANK1 ERROR (Second bank of 256 palettes)
|[[CALENDAR ERROR]]
*VIDEO RAM ERROR ([[VRAM]])
|[[Z80 ERROR]]
*CALENDAR ERROR
|-
*SYSTEM ROM ERROR (BIOS ROM checksum fail)
|'''Display'''
*MEMORY CARD ERROR
|[[File:error_bram.png|160px]]
*Z80 ERROR (no reply to sound command $01)
|[[File:calendar_freeze.png|160px]]
|[[File:error_calendar.png|160px]]
|[[File:error_z80.png|160px]]
|-
|'''Meaning'''
|[[Backup RAM]] R/W error
|[[RTC]] isn't giving Time Pulse
|[[RTC]] ran to slow or too fast
|[[Z80]] didn't reply to command
|}


[[Category:CPUs]]
When a MVS board is powered up without cartridges inserted, the border color around the edges of the crosshatch screen indicates the system ROM region:
 
* Red: Japanese, SPJ2
* Cyan: USA, SPU2
* Blue: Korean/Spanish, SPS2
* Yellow: European
* Green: 6 slot (ROM name ?)
 
=UniBios tests=
 
The [[Universe BIOS]] does not use the above color codes to indicate errors.
 
[[Category:Base system]]
[[Category:Repairs]]

Latest revision as of 05:23, 8 November 2018

Todo: Order of checks.

Cartridge systems

Some information by Channelmaniac.

The AES home console only performs checks when no game is detected.

Error No game WORK RAM ERROR COLOR RAM ERROR VIDEO RAM ERROR SYSTEM ROM ERROR MEMORY CARD ERROR
AES
MVS Crosshatch Screenshot needed
Meaning All tests passed (AES does not test the Z80). Cartridge not detected. 68k user RAM R/W error Palette RAM R/W error VRAM R/W error System ROM checksum mismatch Memory card R/W error (only tested if card present and blank)

MVS checks

Additionnal checks are performed on MVS systems. The SP-S2 system ROM does them in the following order:

  1. Work RAM
  2. Backup RAM
  3. Palette RAM bank 0
  4. Palette RAM bank 1
  5. Low VRAM
  6. High VRAM
  7. RTC
  8. System ROM checksum
  9. Z80
Error BACKUP RAM ERROR Calendar freeze CALENDAR ERROR Z80 ERROR
Display
Meaning Backup RAM R/W error RTC isn't giving Time Pulse RTC ran to slow or too fast Z80 didn't reply to command

When a MVS board is powered up without cartridges inserted, the border color around the edges of the crosshatch screen indicates the system ROM region:

  • Red: Japanese, SPJ2
  • Cyan: USA, SPU2
  • Blue: Korean/Spanish, SPS2
  • Yellow: European
  • Green: 6 slot (ROM name ?)

UniBios tests

The Universe BIOS does not use the above color codes to indicate errors.

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