Author Topic: HDMI HidefNES Board Incompatibility  (Read 27905 times)

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Offline Great Hierophant

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HDMI HidefNES Board Incompatibility
« on: July 13, 2015, 04:49 PM »
As some of you know, kevtris has finalized his HDMI mod board, called the HiDefNES, for the NES and Famicom and has released it to manufacturing.  Unfortunately, it won't work with the Everdrive unless serious work is done at the FPGA programming end.  Please read this post here for more information :

http://forums.nesdev.com/viewtopic.php?f=9&t=12019&view=unread#p150882
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Offline Hanafuda

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Re: HDMI HidefNES Board Incompatibility
« Reply #1 on: July 13, 2015, 04:59 PM »
I'm not savvy on the tech stuff, but am I reading that right that his HDMI setup forces the Famicom/NES to run out of spec, but then he's blaming the Everdrive for causing the incompatibility?


Offline RetroRGB

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Re: HDMI HidefNES Board Incompatibility
« Reply #2 on: July 13, 2015, 11:11 PM »
Krikzz, would you mind commenting on this?  I'm really interested to hear your opinion.

Offline DBloke

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Re: HDMI HidefNES Board Incompatibility
« Reply #3 on: July 14, 2015, 02:30 AM »
1080p on a NES?

Thats a lot of streached distorted pixels
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Offline sammargh

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Re: HDMI HidefNES Board Incompatibility
« Reply #4 on: July 14, 2015, 04:23 AM »
I'm not savvy on the tech stuff, but am I reading that right that his HDMI setup forces the Famicom/NES to run out of spec, but then he's blaming the Everdrive for causing the incompatibility?

Based off the nesdev post the everdrive n8 is using M2 - cpu pin 31 to check when the cpu is ready for bus data. This is not very friendly with the modified timing of the HDMI modification as well as a few CPU/PPU revisions which causes issues with mappers. Sometimes M2 claims it is ready when it isn't causing false reads and corrupted memory.

Offline Hanafuda

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Re: HDMI HidefNES Board Incompatibility
« Reply #5 on: July 14, 2015, 08:43 AM »
I'm not savvy on the tech stuff, but am I reading that right that his HDMI setup forces the Famicom/NES to run out of spec, but then he's blaming the Everdrive for causing the incompatibility?

Based off the nesdev post the everdrive n8 is using M2 - cpu pin 31 to check when the cpu is ready for bus data. This is not very friendly with the modified timing of the HDMI modification as well as a few CPU/PPU revisions which causes issues with mappers. Sometimes M2 claims it is ready when it isn't causing false reads and corrupted memory.

OK, but does the EDN8 have any compatibility issues with the NESRGB mod? I've only got one AV Fami and it's in super condition so I'm not modding it. But I might snag another less pampered one to futz with sometime, so I've been thinking about going ahead and buying the NESRGB kit for future use. But I've been watching the kevtris HDMI situation because it really looks like a superior solution vs. using the RGB board with an upscaler (i.e. Framemeister).
« Last Edit: July 14, 2015, 08:46 AM by Hanafuda »

Offline Kyle

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Re: HDMI HidefNES Board Incompatibility
« Reply #6 on: July 14, 2015, 04:33 PM »
N8 is fine with the RGB mod.

Offline sammargh

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Re: HDMI HidefNES Board Incompatibility
« Reply #7 on: July 15, 2015, 07:12 PM »
I'm not savvy on the tech stuff, but am I reading that right that his HDMI setup forces the Famicom/NES to run out of spec, but then he's blaming the Everdrive for causing the incompatibility?

Based off the nesdev post the everdrive n8 is using M2 - cpu pin 31 to check when the cpu is ready for bus data. This is not very friendly with the modified timing of the HDMI modification as well as a few CPU/PPU revisions which causes issues with mappers. Sometimes M2 claims it is ready when it isn't causing false reads and corrupted memory.

OK, but does the EDN8 have any compatibility issues with the NESRGB mod? I've only got one AV Fami and it's in super condition so I'm not modding it. But I might snag another less pampered one to futz with sometime, so I've been thinking about going ahead and buying the NESRGB kit for future use. But I've been watching the kevtris HDMI situation because it really looks like a superior solution vs. using the RGB board with an upscaler (i.e. Framemeister).

If the N8 works on your NES/Famicom before adding in a NESRGB it will be fine. The problem is that some cpu revisions have M2 lines that send out invalid high/low levels and cause the memory loading to get corrupted. The problem with the HDMI mod is that it clocks entirely differently and just enough to screw up the N8. I use a Famicom N8 just fine in my NESRGB AV Famicom through a Framemeister. Honestly I like it more than the HDMI solution because it has extremely good display zooming which lets you scan the tiles on the border out and not see the random garbage on some games.

Offline nuu

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Re: HDMI HidefNES Board Incompatibility
« Reply #8 on: July 16, 2015, 01:37 AM »
Even if you don't consider the HDMI mod, improving the mappers to solve compatibility problems with those certain CPU revisions would be a good idea.

Offline Great Hierophant

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Re: HDMI HidefNES Board Incompatibility
« Reply #9 on: July 16, 2015, 03:31 AM »
Honestly I like it more than the HDMI solution because it has extremely good display zooming which lets you scan the tiles on the border out and not see the random garbage on some games.

The HiDefNES mod supported cropping early : https://www.youtube.com/watch?v=HNBVzGaworw

kevtris said it could be fixed and the Everdrive's main competition works with the HiDefNES mod. 
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Offline SnoopKatt

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Re: HDMI HidefNES Board Incompatibility
« Reply #10 on: July 20, 2015, 12:54 AM »
N8 is fine with the RGB mod.
It's good for CRT TV's that support it, but eventually RGB/S-video won't be a good option once our CRT's die unless you buy an expensive upscaler (the cheap ones are awful!).

krikzz, kind of a weird question to ask here, but will there be a new N8 revision that would work around this? I know bunnyboy's project is approaching the manufacturing stage, but I'd love to have a stock system and still use an N8.

Offline Great Hierophant

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Re: HDMI HidefNES Board Incompatibility
« Reply #11 on: July 20, 2015, 06:25 AM »
A new revision may not be necessary according to kevtris, but only Krikzz can determine that for sure. 

The HiDefNES mod will be the way to go for many people, either integrated into the Analogue Nt or in a modded system.  There are people who don't want to spend the $300 or so on a Framemeister but will spend half that to get their NES modded.  There is a good opportunity here.
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Offline Fallen Kell

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Re: HDMI HidefNES Board Incompatibility
« Reply #12 on: July 21, 2015, 12:53 AM »
I would hope Kevtris might give a little more information on the problems. I believe the bulk of it is due to where the clock sync is occurring between the Everdrive and the NES hardware resulting in issues with certain CPU/PPU combinations with the Everdrive and issues across the board when the NES's clock rate is changed (either with an overclock or underclock). I would hope this is a fairly simple change to fix as it isn't like you would want to have multiple sections of code sync'ing the clock (even if writing the code in assembler...)

Offline Fallen Kell

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Re: HDMI HidefNES Board Incompatibility
« Reply #13 on: August 23, 2015, 06:30 AM »
Just bumping this now that the boards are starting to get installed on the first test systems. Any idea on if this will get resolved?

Offline moobs

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Re: HDMI HidefNES Board Incompatibility
« Reply #14 on: August 23, 2015, 07:23 PM »
I'd love feedback on this also

I want to modify my AV famicom and the fact this doesn't support the everdrive yet is the reason I'm holding out on buying one

I'd love some information krikzz I'm sure you'll have a lot of users who will be doing this
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