UMC UA6528 = Ricoh 2C02E, not G?

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lidnariq
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Re: UMC UA6528 = Ricoh 2C02E, not G?

Post by lidnariq » Sun Aug 02, 2020 2:18 pm

Ben Boldt wrote:
Sun Aug 02, 2020 10:10 am
OMG please do [make a NESRGB-like thing], let's make it open source! It could support VTxx color tables too! I would help any way I can.
[...]
Based on Tim Worthington's shared info:
All the information on how these work is in thefox's thread here
A prime example is the open source RGB adapter for N64 from borti4938:
I kinda want to make an N64 adapter that can emit 480p/576p. (The N64's video interface supports reprogramming the video mode. But the software only exposed predefined video modes for SDTV). The problem is that the the pixel clock is slow enough (NTSC: ≈12.2MHz, PAL: ≈12.4MHz) that just eliding all the blanking periods doesn't save enough time to emit the de-overscanned 600x450@60Hz or 600x480@50Hz... the secondary problem is that there aren't very many N64 games that use 480i so it wouldn't be very useful. And it's require some RAM in the converter to handle adding all the extra blanking time that'd be omitted.

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zoinknoise
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Re: UMC UA6528 = Ricoh 2C02E, not G?

Post by zoinknoise » Sun Aug 02, 2020 3:39 pm

lidnariq wrote:
Sun Aug 02, 2020 2:18 pm
I kinda want to make an N64 adapter that can emit 480p/576p. (The N64's video interface supports reprogramming the video mode. But the software only exposed predefined video modes for SDTV). The problem is that the the pixel clock is slow enough (NTSC: ≈12.2MHz, PAL: ≈12.4MHz) that just eliding all the blanking periods doesn't save enough time to emit the de-overscanned 600x450@60Hz or 600x480@50Hz... the secondary problem is that there aren't very many N64 games that use 480i so it wouldn't be very useful. And it's require some RAM in the converter to handle adding all the extra blanking time that'd be omitted.
at the risk of hijacking my own thread, that does sound like a nice idea, although i agree–– the need for such a thing is very small with almost every N64 game running in good old 240p. (i believe the N64 was the very last console like that... :cry: *sniff*)

that being said, your version of the adapter would definitely come in very handy for games like RE2 which constantly switch resolutions, and would help eliminate the disruptions they cause in a modern display setup.

i am actually seeing this kind of design overkill in other retro gaming products as well––have you noticed how the Everdrive N8 was just redesigned to support 16MB ROM sizes, a realtime clock, and other wild shit? none of that stuff is needed by any retail game, but now the philosophy seems to be getting that last one percent right and supporting absolutely everything seamlessly.

IMO, the idea of making special considerations for those very few N64 games that use 480i seems right in line with the zeitgeist.

lidnariq
Posts: 9697
Joined: Sun Apr 13, 2008 11:12 am
Location: Seattle

Re: UMC UA6528 = Ricoh 2C02E, not G?

Post by lidnariq » Sun Aug 02, 2020 7:38 pm

Looks like marshallh's UltraHDMI has more than enough rope for it, and the rest of the puzzle is "just" ROM hacking.

And deciding whether 480i60 gets patched to 450x450@60Hz (full height) or 580x349@60Hz (full width) or 516x387@60Hz (maximum 4:3)... or the N64 gets overclocked just so that the VI is also overclocked enough to emit a full 580x450@60Hz.

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