Looking for a homebrew to display a white screen on GX4000

[ArcadeTV]

Hello programmers,
I'd like to measure the video signals inside a GX4000 with my scope and therefor I'm in need of a software that can be burned to an eeprom and displays a solid pure white screen.
If you feel adventurous it would be awesome if there was an option to toggle between pure white, red, green, blue and black screens with the joypad.

Can anyone of you write and compile such a thing?
Any help with this is very much appreciated!
Thanks!

[CraigsBar]

Hello programmers,
I'd like to measure the video signals inside a GX4000 with my scope and therefor I'm in need of a software that can be burned to an eeprom and displays a solid pure white screen.
If you feel adventurous it would be awesome if there was an option to toggle between pure white, red, green, blue and black screens with the joypad.

Can anyone of you write and compile such a thing?
Any help with this is very much appreciated!
Thanks!

I think the test/ debug cart does that. I am sure @arnoldemu will correct me if it doesn't.

[ArcadeTV]

That would be great! Thanks for sharing that information.
Is this some kindo of service-cart that was available for technicians back in the days?
I couldn't find any info on google about it, is it for cpc in general or GX4000-exclusive?
Need to get my hands on that

[Bryce]

Unfortunately our Wiki lacks any information at all about this cartridge, but you can read a bit here and download the ROM image. However I'm not sure it's usable without a keyboard?

http://www.grimware.org/doku.php/documentations/hardware/amstrad.cartridge.released

Bryce.

[ArcadeTV]

Thanks!!
Are we talking about the system-cart or the diagnostic-cart?

[CraigsBar]

Thanks!!
Are we talking about the system-cart or the diagnostic-cart?

this one I think will allow rgb testing with all screen colours.

http://www.winape.net/cart/arn5diag.zip

[ArcadeTV]

Nice! 
Just tested it in Arnold and it seems very usuable for my purpose.
Will it run on the GX4000 and can it be controlled with the joypad?

I have bought another burnin rubber cart to use it with the rom,
any special treatment needed for burning the eeprom? byteswapping maybe?

THANKS!!!

[dragon]

Nice! 
Just tested it in Arnold and it seems very usuable for my purpose.
Will it run on the GX4000 and can it be controlled with the joypad?

I have bought another burnin rubber cart to use it with the rom,
any special treatment needed for burning the eeprom? byteswapping maybe?

THANKS!!!

Nothing special simply burn  it. If you don't have an eeprom uv eraser, use a flash 29f010 and you can reuse the chip.

[ArcadeTV]

That would have been my next question 
Thanks guys! I'll report back with results!

[Bryce]

The System cartridge is just a cartridge with the Plus Firmware and BASIC (and Burning Rubber) on it (The CPC Plus doesn't have any ROMs inside).

No special treatment or byteswaps needed. Just make sure you use the BIN version of the file, not the CPR version which is meant for emulators only. If that zip only includes the CPR file you can convert it with this: CPRTools - Convert between CPR and BIN cartridge formats

Also, only use 2Mbit EEPROMs at most, the 4Mbit EEPROMs have a slightly different pinout.

Bryce.

[ArcadeTV]

Thank you guys so much.
Guess I'll be busy for a while now