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General Category => Technical Support - General => Topic started by: shock__ on 19:59, 07 October 17

Title: 464 to 6128 spec woes
Post by: shock__ on 19:59, 07 October 17
Hey there,
I recently got a broken 464 which I fixed (ROM + 373 + 244 broken, shortcircuit on tape PCB) and upgraded to 6128 specs by adding a GAL, second RAM bank and swapping ROMs.
So far it seems to work nicely, 'Digital Orgasm' detects a 6128 with 128k RAM, nilquader's RAM tester checks out without errors.
Sadly the demo pheelone by condense (http://www.pouet.net/prod.php?which=53498) does not work correctly. The first part (where it loads) looses sync rythmically, resulting in a rolling image and when the actual demo should start the screen just freezes. The CPC currently has a CRTC type 2 (actually tried a MC6845 and a HD68B45SP), but I've already ordered a type 1. Gate array is an Amstrad 40007. GAL is a Lattice GAL16V8D-15 using the fixed jedec by gerald (http://www.cpcwiki.eu/index.php/PAL16L8). Other than that the machine has a DDI-1 interface, with a 3" drive connected as A: and a 3.5" drive connected as B: - which seem to work quite well (not completely without woes since the B: drive occasionally would have troubles detecting the put in disc and the LED being constantly on for some reason).

Any ideas what might cause the demo to crash? In WinAPE it works in a CRTC type 2 configuration. Other demos like DemoIzArt, Digital Orgasm, Midline Process or Phortem work nicely.
Title: Re: 464 to 6128 spec woes
Post by: shock__ on 19:01, 08 October 17
Maybe anyone can check it on a 6128 with a CRTC type 2?
Either way I should have a CRTC type 0 and type 1 in the mail within the next few days - I hope that's the issue there.
Title: Re: 464 to 6128 spec woes
Post by: gerald on 19:59, 09 October 17
Quote from: shock__ on 19:01, 08 October 17
Maybe anyone can check it on a 6128 with a CRTC type 2?
Either way I should have a CRTC type 0 and type 1 in the mail within the next few days - I hope that's the issue there.
Does not work on a CTRC2. Tested with the original AMSTRAD PAL and the fixed one.
Run fine with a CRTC0 or CRTC1 with both PAL  ;)
Title: Re: 464 to 6128 spec woes
Post by: shock__ on 20:53, 09 October 17
Thanks for the heads up gerald :)
I should get a Hitachi CRTC 0 and an UMC CRTC 1 within the next few days and will report back.
Title: Re: 464 to 6128 spec woes
Post by: shock__ on 12:51, 12 October 17
HD6845P is another incarnation of the CRTC 2? Oh man.
Now let's hope the UMC 6845R I ordered at least verifies as a CRTC 1
Title: Re: 464 to 6128 spec woes
Post by: Bryce on 13:27, 12 October 17
The P version was never used in CPCs though.

Bryce.
Title: Re: 464 to 6128 spec woes
Post by: shock__ on 18:17, 12 October 17
Seems like it ... just like the HD68B45SP I have.
To be perfectly honest it's getting kinda annoying to get a CRTC 0/1 :( I guess I might soon have enough spare chips to build my own KC Compact ;)
Title: Re: 464 to 6128 spec woes
Post by: shock__ on 11:48, 14 October 17
CRTC 1 has arrived and all is well.
Pheelone and Batman Forever now working flawlessly.
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