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Post by Peer on Jan 17, 2024 5:35:15 GMT -5
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Post by playvectrex on Jan 20, 2024 17:52:22 GMT -5
Nice pictures of everything, thanks for sharing!
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Post by Peer on Apr 20, 2024 2:41:26 GMT -5
For those interested:
The ScopeTrex board layout is known to have a minor flaw. The interrupt line is not connected, so cartridges and games that use interrupts (e.g. Bedlam) do not work properly. We have fixed this on my ScopeTrex by adding an additional wire, and now interrupts work. The procedure is rather easy, so if anyone wants to do the same on their board, I'd be glad to help.
Many Cheers, Peer
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Post by playvectrex on Apr 22, 2024 11:14:04 GMT -5
For those interested:
The ScopeTrex board layout is known to have a minor flaw. The interrupt line is not connected, so cartridges and games that use interrupts (e.g. Bedlam) do not work properly. We have fixed this on my ScopeTrex by adding an additional wire, and now interrupts work. The procedure is rather easy, so if anyone wants to do the same on their board, I'd be glad to help.
Many Cheers, Peer
Bedlam uses the interrupt line?? Like the /IRQ pin?? Please post more about this... I'm really curious  |
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Post by Peer on Apr 22, 2024 11:28:07 GMT -5
Bedlam uses the interrupt line?? Like the /IRQ pin?? Please post more about this... I'm really curious Hehe, glad you asked  The analysis is from January 2023:
Many Cheers, Peer
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Post by playvectrex on Apr 29, 2024 23:27:54 GMT -5
Bedlam uses the interrupt line?? Like the /IRQ pin?? Please post more about this... I'm really curious Hehe, glad you asked The analysis is from January 2023:
Many Cheers, Peer
Wow! Very impressive research and code analysis I played it online just now, and I can tell you it's going to be tough starting any faster than it already was, but will give it a go on real hardware. Re: "Or this is some kind of inside joke, as 49407 decimal corresponds C0FF hex, which could be read as "coff(ee)" ;-)" I think you might have gone too deep on this one ;-) but that would be insanely cool if that was really the reason for that specific refresh rate. I bet you are right, they just tweaked it until it felt right. I understand now how Bedlam uses the interrupt timer of the VIA(6522A), but I didn't see a mention of the physical hardware connection between VIA pin 21 (/IRQ) and the MCU pin 3 (/IRQ). I'm guessing that's the wire you had to add to your Scopetrex? |
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Post by Peer on May 4, 2024 9:36:26 GMT -5
I understand now how Bedlam uses the interrupt timer of the VIA(6522A), but I didn't see a mention of the physical hardware connection between VIA pin 21 (/IRQ) and the MCU pin 3 (/IRQ). I'm guessing that's the wire you had to add to your Scopetrex? Yes. I had come across this link here: www.vecfever.com/2020/09/07/scopetrex-other-new-vectrex-cpu-pcbs-firmware-v1-31/The issue is mentioned in the second and third paragraph. |
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Post by kokovec on May 22, 2024 22:35:47 GMT -5
A Hameg scope sighting!
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Post by Peer on May 23, 2024 0:52:19 GMT -5
Yes, a treasure from the past. These explorations are called "digital archeology" for a reason |
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Post by Peer on Jun 4, 2024 10:42:11 GMT -5
The student who designed the case for the ScopeTrex board, which can be seen in some of the pictures, has kindly agreed to share the 3D printer files. I have added a download section to the project page.
Many Cheers, Peer
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The analysis is from January 2023: