[AVS] HDMI Nes

[MotoRacer]

 

 

 

 

 

I was about to say then.. Why do you even care about having the hardware? Just emulate and call it a day. No one will shame you for it.

 

I agree, haha. Just, playing on a "proper" console is always nice. I found playing games on the PC to be pretty annoying, so at least this is on a console... er, sega console, but console none the less, haha

 

Again, for 200 this is beyond me, I simply was saying systems like this could be nice in the future as consoles start to age / as people start to buy TVs without composite/s-video connections and aren't crazy enough to buy a BVM for old console play.

[Andromeda Stardust]

Brian Parker (founder of RetroUSB) is waiting for shipment from China.

[Noah98]

AVS is up for preorder now! I got a regular edition and the launch game Assimilate. Get one while you can

 

www.retrousb.com

Edited August 8, 2016 by Noah98

[romeoteknik]

I also pre-ordered.

[Austin]

Thanks for the heads up, I just pre-ordered as well. I got to handle one of these things at ReplayFX in Pittsburgh, PA just this past weekend. Excellent build quality, good texture feel on the unit. I'm definitely looking forward to it!

[Noah98]

This should be a great system at an affordable price. I like the way Brian's doing launch games with it as well. Very cool!

[Newsdee]

Does anybody know the size of the FPGA chip used for it? From the pictures it's a Xilinx Spartan-6 but can't tell the model.

 

I'm guessing it's the SLX16 with ~15K LE but maybe they managed to squeeze the core into a smaller version.

[Andromeda Stardust]

Got a standard AVS this afternoon with Solaris (Xmas 2013 Shmup), Twelve Seconds (Xmas 2015 tough as balls platformer), Assimilate (alien abduction homebrew), and A Winner is You (music cart).

 

Does anybody know the size of the FPGA chip used for it? From the pictures it's a Xilinx Spartan-6 but can't tell the model.

I'm guessing it's the SLX16 with ~15K LE but maybe they managed to squeeze the core into a smaller version.

I have no idea. Someone will do a teardown eventually and list codes on all the chips and what they do.

[killersquirel]

I preordered one as well along with a More Glider cart. Out of curiosity can the FGPA chip be reprogrammed for any future updates?

[Shawn]

Most of those games listed along side of the AVS are not new titles.

[Newsdee]

Out of curiosity can the FGPA chip be reprogrammed for any future updates?

Yes, it upgrades via USB.

[Andromeda Stardust]

Most of those games listed along side of the AVS are not new titles.

You are probably on to something here, however nearly all of them were previously discontinued or unavailable.

• Quadralords = Enhanced remake of 8-bit Xmas 2011, which itself was a port of Atari Warlords.
• Solaris = Enhanced remake of 8-bit Xmas 2013.
• Twelve Seconds = Enhanced remake of 8-bit Xmas 2015.
• More Glider = Enhanced remake of Glider.
• Power Coloring = Enhanced remake of Color a Dinosaur.
• Assimilate = Reissue of discontinued original by NESsylum.

Plus one music cart:

• A Winner Is You = Brand new music cart featuring live recordings of remixed NES tunes. Not technically a game.

That said, I did preorder four out of the seven "launch" titles, including the music cart!

[cybercylon]

That console is a very worthy endeavor.

 

Unfortunately, these things seem to be available at a bad time....

[phoenixdownita]

If this console does the same thing Kevtris did for the HDMI NES board then they have to alter the timing of the CPU/PPU in order to stick to the HDMI 60fps strict guidelines (whereas composite is around 59.something [it should be 59.94 to be perfect NTSC but they never were that picky]), given they claim no lag I see no other solution as full screen buffer is not possible in such setting.

[i am not sure the same problem existed in PAL land or 50Hz was never wobbled down for compatibility]

 

Anyway in doing so they lose 1% (or whereabouts) of CPU/PPU time per VBL .... I doubt the PPU time matters but what about the CPU time?

Is there any game that changes its behavior significantly by losing 1% CPU? SD2SNES had a little hiccup in the CX4 implementation in that it was running faster (can't remember how much) and one of the 2 Megamans presentation behaved differently (not sure the impact on gameplay though).

 

I would venture that any game that plays in the background as the user does its actions (like AI based turn game) is a tad easier with that loss of 1%, any game that timed exactly its instruction count may come up short as there may be no time for that extra 1 or 2 instructions in the VBlank.

 

Anyone can chime in to say if he/she noticed anything different?

[Great Hierophant]

If this console does the same thing Kevtris did for the HDMI NES board then they have to alter the timing of the CPU/PPU in order to stick to the HDMI 60fps strict guidelines (whereas composite is around 59.something [it should be 59.94 to be perfect NTSC but they never were that picky]), given they claim no lag I see no other solution as full screen buffer is not possible in such setting.

[i am not sure the same problem existed in PAL land or 50Hz was never wobbled down for compatibility]

 

Anyway in doing so they lose 1% (or whereabouts) of CPU/PPU time per VBL .... I doubt the PPU time matters but what about the CPU time?

Is there any game that changes its behavior significantly by losing 1% CPU? SD2SNES had a little hiccup in the CX4 implementation in that it was running faster (can't remember how much) and one of the 2 Megamans presentation behaved differently (not sure the impact on gameplay though).

 

I would venture that any game that plays in the background as the user does its actions (like AI based turn game) is a tad easier with that loss of 1%, any game that timed exactly its instruction count may come up short as there may be no time for that extra 1 or 2 instructions in the VBlank.

 

Anyone can chime in to say if he/she noticed anything different?

 

Canonical NTSC has a scan rate of 59.94Hz but the NES and the SNES have a scan rate of 60.0988Hz. Analog CRTs were much more lenient when it came to out-of-spec signals than digital HDTVs. The HDMI strict 60Hz scan rate is .16% slower than the NES and SNES real hardware scan rate, not 1%.

Edited August 11, 2016 by Great Hierophant

[phoenixdownita]

 

Canonical NTSC has a scan rate of 59.94Hz but the NES and the SNES have a scan rate of 60.0988Hz. Analog CRTs were much more lenient when it came to out-of-spec signals than digital HDTVs. The HDMI strict 60Hz scan rate is .16% slower than the NES and SNES real hardware scan rate, not 1%.

So they are slowing down the CPU by 0.16%, which is 1/7 of what I thought.

Still, hand optimized code in the VBL may take advantage of "a couple of instructions". At 1.79MHZ [the NES CPU clock] 0.16% is 2.8Khz, many instructions for the 6502 where at 2 clock cycles so that leaves ~ 1.4K instructions [likely less than that but still] which divided by 60 frames is around 20 instructions per frame.

[Andromeda Stardust]

 

Canonical NTSC has a scan rate of 59.94Hz but the NES and the SNES have a scan rate of 60.0988Hz. Analog CRTs were much more lenient when it came to out-of-spec signals than digital HDTVs. The HDMI strict 60Hz scan rate is .16% slower than the NES and SNES real hardware scan rate, not 1%.

 

Exactly. Does anyone really believe that slowing the NES down by .16% will cause a noticeable change in performance? Also slowing it down ever so slightly involves padding a few extra CPU cycles, not taking them away. No human player can detect such infinitesimal change.

 

The 60.09 scan rate is largely a byproduct of the fact that the NES runs 240p (262 scanlines every frame) as opposed to 480i (262+263 scanlines every other frame) losing a half scanline wiith every refresh. All 240p consoles do this to some degree. Atari is a bit worse though with an incorrect clock count per scanline, 228 instead of 228.5. That's enough to break compatibility with my Hauppauge USB capture device.

 

All that is needed to momentarily preserve the frame rate and lock it into 59.94Hz or 60Hz is to briefly halt CPU/PPU execution for a few cycles during the V-blank period, resulting in 100% perfect HDMI sync and 100% perfect NES cycle accuracy.

 

So they are slowing down the CPU by 0.16%, which is 1/6 of what I thought.

Still, hand optimized code in the VBL may take advantage of "a couple of instructions" at 1.79MHZ [the NES CPU clock], 0.16% is 2.8Khz as many instructions for the 6502 where at 2 cycles so that leaves ~ 1.4K instructions [likely less than that but still].

Not if you halt the CPU for a few cycles instead of letting it run. Either way, I doubt any games would break as a result.

[phoenixdownita]

...

 

Not if you halt the CPU for a few cycles instead of letting it run. Either way, I doubt any games would break as a result.

I'm with you on this, but I was wondering if anyone found even one game with either Kevtris board or this NES AV that does show a divergence.

Just curiosity, likely I wouldn't care about those games.

 

{BTW I did a quick check and the NES CPU does not have a HALT signal (on old revisions it seems the TST signal did that) so unless you freeze the core and the CPU is completely static there's no "easy" way to HALT it, maybe slowing the CLK down in the KHz range would do the trick but I am not sure if that's what happens here}

[Andromeda Stardust]

I'm with you on this, but I was wondering if anyone found even one game with either Kevtris board or this NES AV that does show a divergence.

Just curiosity, likely I wouldn't care about those games.

 

{BTW I did a quick check and the NES CPU does not have a HALT signal (on old revisions it seems the TST signal did that) so unless you freeze the core and the CPU is completely static there's no "easy" way to HALT it, maybe slowing the CLK down in the KHz range would do the trick but I am not sure if that's what happens here}

For the record, the AVS uses FPGA instead of NES CPU, so it would be trivial to halt instructions momentarily or even bend the clock speed by the infinitesimal .16% amount you speak of.

 

Also you can easily halt the NES CPU or other 6502 derivative by simply stopping the clock signal supplied by the crystal. The Atari pause kit does exactly this to suspend Atari 2600 games.

[Newsdee]

One thing worth noting is that in theory this hardware is reconfigurable, so as long the specific logic fits the FPGA, it could be softmodded into other consoles. Add some kind of cart adapter and you could run other libraries.

 

But it would be impractical to do so, it would need a firmware update to switch systems (can only have one at a time). Also they may have made HW compromises to get the NES to run and save costs that would be annoying to work around.

 

In contrast the MiST has (and the Kevtris Z3000 will have) a much bigger FPGA chip plus have more hardware "leeway" to be more flexible.

 

I know it's not at all for the intended audience, but hopefully we could see some interesting experiments out of this machine.

Edited August 11, 2016 by Newsdee

[Austin]

This hasn't been bumped yet? The AVS has shipped and many of us have received it. Needless to say, it is awesome.

[Newsdee]

so.. what's your impressions compared to emulators?

[Austin]

I don't know how it compares to modern emulators (I don't use them), but what I can say is it seems to replicate the NES experience nearly 100%. Full speed, no glitches, audio is perfect (even the Japanese Castlevania III), scanline options for people who don't like the crisp pixel-perfect emulator look, etc. Oh, and zero input lag (that's kind of a big one).

[godslabrat]

Really want to know about compatibility with unlicensed titles and other games that tend to not get a thorough playtest. Castlevania III is a good start, but let's see if it can handle the funkiness of Sunday Sunday, Pesterminator, Action 52, etc.

[Gentlegamer]

It passed the Castlvania III test, that's all that matters.