New yerar, new CPC board

[Piotr]

Ok i do some tests and : On orginal HAL (from 6128)  Just CPC and XMEM working ok, if i replace HAL to programmed GAL 16v8d 15LP is a lot artefact.... Work in progress...

[Joseman]

Amstrad HAL rulez!!!! 

[CraigsBar]

Ok i do some tests and : On orginal HAL (from 6128)  Just CPC and XMEM working ok, if i replace HAL to programmed GAL 16v8d 15LP is a lot artefact.... Work in progress...

Back to my Spare Parts bin... YES I have an Original HAL... One Quick Swap later and with the Symbiface connected I have zero Artifacts on either Batman Forever or CPM Plus.


Confirmed that the issue seems to be the GAL vs Original HAL.


I'll keep the HAL in the JustCPC for now..


If however when you find the cause, and create new GALs that work, can I have one please so my spare HAL can return to the parts bin. Unlike Z80's and RAM I only have 1 spare HAL.


Thanks for your work. Now to order replacement Xmem and Xmass.

[Piotr]

Is also second option, not solution of course. You can connect pin 4 GAL to GND, artefacting gone but you lose 512 ram from xmem . Anyway i still working to resolve this.

[CraigsBar]

Is also second option, not solution of course. You can connect pin 4 GAL to GND, artefacting gone but you lose 512 ram from xmem . Anyway i still working to resolve this.

Running fine with an original half. This does not fix the joypad issue however. Any ideas on that one?

[gerald]

Running fine with an original half. This does not fix the joypad issue however. Any ideas on that one?

Is it an AY-3-8912 or AY-3-8912A ?
If its a A variant, what you see is expected. You need to add pull-up on the keyboard row.
The PS2CPC used for the keyboard handling is not affected by that because it is driving high the pads for 125ns (side effect of AVR IO handling)

[CraigsBar]

Is it an AY-3-8912 or AY-3-8912A ?
If its a A variant, what you see is expected. You need to add pull-up on the keyboard row.
The PS2CPC used for the keyboard handling is not affected by that because it is driving high the pads for 125ns (side effect of AVR IO handling)

Yep. It's an A variant. Back to the parts bin then although I suspect I have to desolder an ay.

[CraigsBar]

Yep. It's an A variant. Back to the parts bin then although I suspect I have to desolder an ay.

AY-3-8912 desoldered, cleaned up and fitted. Now the joystick and keyboard work together.

OK might get a new AY as this one has had a long life already!

[TotO]

Unfortunately I just got my power leads back to front and fried my xmem and X-mass it seems they really dislike 12v. @TotO , do you think they are fixable? Or should I just order new ones?

Send them back, I will see what I can do. 

[gerald]

Back to my Spare Parts bin... YES I have an Original HAL... One Quick Swap later and with the Symbiface connected I have zero Artifacts on either Batman Forever or CPM Plus.
Confirmed that the issue seems to be the GAL vs Original HAL.

Can you check the GAL in a 6128 ?

[Porchy]

Insterested in hearing results of any GAL testing.
I was only able to test games on the 6128 when I made it and don't have any expansions to test out.
Worth noting that a GAL device has a max propagation time of 3.5ns compared to the HAL which is 35ns max. Nothing I can do about that if it turns out to be the issue.
It also entirely possible I missed something completely. I did implement the /RAMDIS operation but never did test it.

[Bryce]

31.5ns difference isn't much for a system that used RAM ICs with a 150ns reaction time. I can't imagine that that could be the issue. As well as that, the original CPC6128 doesn't have an issue with using a GAL.

Bryce.

[CraigsBar]

31.5ns difference isn't much for a system that used RAM ICs with a 150ns reaction time. I can't imagine that that could be the issue. As well as that, the original CPC6128 doesn't have an issue with using a GAL.

Bryce.

Maybe later on, after dinner I'll check my cpc6128 with the justcpc gal

[Porchy]

31.5ns difference isn't much for a system that used RAM ICs with a 150ns reaction time. I can't imagine that that could be the issue. As well as that, the original CPC6128 doesn't have an issue with using a GAL.

Bryce.

Very good point.
I work a lot on arcade hardware and have come across instances where a certain speed of GAL chip just won't work properly and a slower for faster device is needed.

[CraigsBar]

Maybe later on, after dinner I'll check my cpc6128 with the justcpc gal

OK. As promised... Gal in my Schneider CPC 6128 and it has artifacts just like the justcpc.

[Bryce]

Wow, wasn't expecting that. Can you tell me how you get the artifacts. I have a 6128 with GAL here, I'd like to test it.

Bryce.

[CraigsBar]

Wow, wasn't expecting that. Can you tell me how you get the artifacts. I have a 6128 with GAL here, I'd like to test it.

Bryce.

Sure.... Attach a memory expansion (xmem and symbiface both do the same here) and boot CPM either from ROM |ems or disk |CPM. The screen will become a snowstorm of white artifacts. No mem expansion, no problem.

Oh another oddity with the JustCPC. The shift menu in parados does not show unless you press alt as well. It still works with just shift, but the screen is not updated.

[Bryce]

I'll test it with a DKTronics 256K expansion.

Bryce.

[CraigsBar]

I'll test it with a DKTronics 256K expansion.

Bryce.

The only dktronics kit I have is a silicon disk.... With suspect ram. When I get my xmem fixed, it's yours if you need to complete the set

[gerald]

Oh another oddity with the JustCPC. The shift menu in parados does not show unless you press alt as well. It still works with just shift, but the screen is not updated.

I will have a look at that

[Bryce]

The only dktronics kit I have is a silicon disk.... With suspect ram. When I get my xmem fixed, it's yours if you need to complete the set

Cool. I'll send you a PM in a minute about that and other IMPORTANT things (Beer drinking).

Bryce.

[Jungsi]

Today I've received my Just CPC :-)
I've a short try with a power supply 2A 1,5V and it starts up.
Do I have to pay attention on any device I want to use with it?
i.e. X-MEM, X-Mass, Multiface or any other of the latest interfaces?
What kind of case do you use for your Just CPC?

[TFM]

Instead of the 1,5 V you should use 12 Volt. The holes in the board are fine for a Small PC case, they got a special name which I don't remember.

[TotO]

Take care!
CraigsBar have fried his X-MEM and X-MASS by plugging them on it.
I would like to know the issue before the need to fix more boards...

[Piotr]

I don't know how can fried cards, on board is only 5 volt so is strange. Anyway, soon i post small service pack for fix issues with X-mem and GAL . Please be patient.