Small board for diagnostics or game cartridge

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By Alexey

Guardian (2407)

Alexey's picture

24-06-2017, 19:18

I always wanted to have a small cheap board with a diagnostics ROM, so I made this simple cartridge:

I use this board with TESTRAM.ROM as a diagnostics cartridge. Very cheap and effective. I also made a special board with a 50 pin slot connector - if you have soldered a Winbond W27C512 chip onto the cartridge board, you can re-program the cartridge with a MiniPro EEPROM programmer (or similar) without desoldering the chip.

The board is suitable for 8, 16, 32, 49 and 64kb ROMs without mapper. So it will work for MSX games as well.

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By Alexey

Guardian (2407)

Alexey's picture

25-06-2017, 14:45

I challenge the MSX developers to write a proper diagnostics ROM to be used by the community in a simple cartridge like this. The ROM should be max. 64k in size and should not require a mapper.

The ROM should be able to test:

- RAM
- VRAM
- RAM mapper functions
- PSG
- FMPAC (internal)
- VDP (screens, colors, pallette, fonts, sprites)
- keyboard (keys + lights)
- attached peripherals (joystick, printer)
- board's components (z80, MSX Engine, VDP, PPI, RTC, etc)

Because during a diagnostics the video or audio may be not functioning properly, its good to first ask a user to confirm that he sees the screen output and if he hears the beeps. If there's no video, the RAM+mapper+VRAM tests should run automatically and the feedback should be given by a series of beeps. If there's no video or audio, the feedback can be given by flashing a CAPS light.

We celebrated 30 years of MSX already, but we still have no proper diagnostics cartridge like Commodore guys have (Dead Test cartridge). We have TETRAM.ROM, which is great, but very simple. The TESTMAP.COM is detailed, but can be run only from DOS. Are there any other programs to test MSX? I don't know any.

So, I challenge the hardcore MSX developers to write the proper diagnostics software. As our MSXs are getting older and older, we will see a lot of malfunctions of our beloved computers within next few years. And a diagnostics cartridge will help to bring them back to life by detecting the source of the problems.

By hardwaremaker

Master (223)

hardwaremaker's picture

26-06-2017, 08:41

I use similar boards, but with zero insertion force socket for the eprom chip.

By Alexey

Guardian (2407)

Alexey's picture

26-06-2017, 11:53

hardwaremaker wrote:

I use similar boards, but with zero insertion force socket for the eprom chip.

Could you share a picture please? The ZIF sockets I've seen were too big to fit into a cartridge case.

By geijoenr

Expert (93)

geijoenr's picture

26-06-2017, 16:22

Hi Alexey,
I think I can do a first version of that ROM.

do you mean something like this? https://www.youtube.com/watch?v=ihyKErwiy5k

By Louthrax

Prophet (2084)

Louthrax's picture

26-06-2017, 16:39

geijoenr wrote:

Hi Alexey,
I think I can do a first version of that ROM.

do you mean something like this? https://www.youtube.com/watch?v=ihyKErwiy5k

Hi geijoenr,

That tool you showed in the video looks exactly like what's needed on MSX. That's great if you could start something like that :) !

I have some suggestions in mind on top of what Alexey already mentionned:

  • Allow the UI to be joystick controlled. I often have the keyboard removed from the main board when checking things, so that could be super useful!
  • Could be cool to have the project open-sourced. I'm pretty sure some people will have specific tests to add or tweak.
  • I do not want to restart a recent and looooooooooong thread about that subject, but using BIOS functions and reading VDP ports from BIOS would allow that tool to work on more machines (and I guess we have no big performance need here).
  • A function to display the CRC32 of the ROMs found could also be interesting (Grauw has fully working sources if you want to go for it).

By Alexey

Guardian (2407)

Alexey's picture

26-06-2017, 17:29

geijoenr wrote:

Hi Alexey,
I think I can do a first version of that ROM.
do you mean something like this? https://www.youtube.com/watch?v=ihyKErwiy5k

Yes, I meant something like the C64 Dead Test cartridge that was shown in the video. A bit improved version actually to run automated tests in case a user can't see the screen output, hear the audio or press necessary keys. We need to think of a way to provide feedback on the run tests using something that actually works (screen flashes, coded beeps, blinking CAPS light, etc.). Would be awesome to have this kind of ROM for initial diagnostics!

A floppy drive test could be useful too.

By Grauw

Ascended (8460)

Grauw's picture

26-06-2017, 18:53

Printing the report Big smile.

(I’m joking, but also maybe I’m not Smile.)

By hardwaremaker

Master (223)

hardwaremaker's picture

26-06-2017, 21:35

Alexey wrote:
hardwaremaker wrote:

I use similar boards, but with zero insertion force socket for the eprom chip.

Could you share a picture please? The ZIF sockets I've seen were too big to fit into a cartridge case.

Yes, the ZIF socket is too big. I use this cartridges without cartridge case.

By rderooy

Hero (582)

rderooy's picture

27-06-2017, 08:25

Why not put a few LEDs, or a seven-segment display on it to indicate it has power and has completed the RAM test at least. That way you will know something in case there are problems with the video output or the keyboard.

By Alexey

Guardian (2407)

Alexey's picture

27-06-2017, 13:16

rderooy wrote:

Why not put a few LEDs, or a seven-segment display on it to indicate it has power and has completed the RAM test at least. That way you will know something in case there are problems with the video output or the keyboard.

The idea to have a specialized test cartridge with LEDs, numeric display and cables that can be inserted into joystick ports, printer port, cassette port and even into video outputs for checking for proper signals in those connectors is nice, but it's way more complicated than writing a diagnostics ROM. This requires at least a hardcore hardware and software developers' efforts + prototyping + testing. And there's no guarantee that the cartridge will work on all MSXs due to design differences. Just remember Daewoos...

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