New PCB rev on the horizon

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nicksen782
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Re: New PCB rev on the horizon

Post by nicksen782 » Sun Apr 12, 2015 6:50 pm

The external ram might happen. It would probably just be used to preload data from sd... Assuming it is faster than sd. There is a recent forum thread on it. Best part of the community is the helpfulness but especially studying source code. I really believe that some big things are going to happen for the next round of games.

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uze6666
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Re: New PCB rev on the horizon

Post by uze6666 » Tue Apr 14, 2015 2:10 am

I have just discovered this community and would like to know if a later version of the schematics would include external SRAM or Not?
Sorry, if i say nonsense phrase (i am french lol) but it would allow people developping games more space for creativity? And the ability to really exploit the uzebox potential not?
I am still discovering so maybe it is not realistic :-)
If I end up putting the esp8266, the SPI will go along. The big problem with it though is that it is slooow. Reading a single byte randomly with take ~110 clocks cycles vs 2 for the internal sram. In the best case where you read a stream of sequential bytes, it takes 18 cycles. That's still 10 times slower than the internal sram. Btw it's exactly the same speed as the SD interface. So it's uses seems limited to buffering and storing lots of modifiable data, huge maps, etc. A cool usage I'd like to see would be to somehow enhance normal games that works without the added hardware. But again most use case I can think of (like big PCM samples) could be done with the SD card.
For the end, i would dream to add a expansion cartridge if possible (for homebrew games) even if i know there is the SDcard.. it is not the same feel
Ahhh yes the cartridge idea...it's been a while! :) Technically you can already do it in two manners. 1) replace the DIP40 socket with 40 pin slot and put the ATmega644 on the cartridges. You're limited to one game only. 2)Put the Atmega644 *and* sd card on the cart pcb to simulate a 100-in-1 cartridge. Perhaps I'll try it for the kicks someday, no excuses now that I have a 3D printer!

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Re: New PCB rev on the horizon

Post by D3thAdd3r » Tue Apr 14, 2015 3:47 pm

I'm sold that the ram is the ticket to next generation games for things that only need slow streaming from pre-loaded resources. You can stream "unlimited" music from it easily, loaded from SD, and it takes no flash space(and you can free the SD to do something else). Or 4-way scrolling on a very large game world that also takes no flash. You might simultaneously have many, flash free, PCM sound effects/instrument patches available to enhance sound. If it's there, clever people will find a use.
For the end, i would dream to add a expansion cartridge if possible (for homebrew games) even if i know there is the SDcard.. it is not the same feel
Heh, I can understand the appeal even at the expense of convenience. Perhaps the simplest way is to route the SD traces to a cartridge connector. Put a small 256M SD with a single rom image inside the cartridge(with SD traces to the corresponding console pins), and have some special file on that SD that tells the bootloader to automatically load this rom without a menu. That should provide the same "feel". If you were lucky, you might occasionally experience trouble with the pins making good contact not allowing the SD to work, requiring you to re-seat it(and blow on it for no reason). Part of the nostalgia! :lol:

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Re: New PCB rev on the horizon

Post by neslou » Tue Apr 14, 2015 7:08 pm

I see that I am not crazy with my "cartridge" lol :D
For the RAM I have to admit that I haven't already read all the forum....so I wasn't aware regarding the slow aspect.
To be follow so... but from now, I have to stop dreaming and beginning :D
1°) Succeed to do One..then improve it for my enclosure :-)

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Re: New PCB rev on the horizon

Post by uze6666 » Wed Apr 15, 2015 4:06 am

Put a small 256M SD with a single rom image inside the cartridge(with SD traces to the corresponding console pins), and have some special file on that SD that tells the bootloader to automatically load this rom without a menu.
Would be totally awesome, specially for big sd-based games like Tornado2000 or AlterEgo! :D

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Re: New PCB rev on the horizon

Post by D3thAdd3r » Thu Jun 25, 2015 3:08 am

Not sure the correct place to put this question so hopefully this is good.

I'm interested in getting RGB out of the standard Uzebox kit via the A/V header as Alec mentioned. It seems it should work, but I would like this to fit into the 3d printed case hopefully with no wires sticking out. I had an idea to hack the S-Video port and run some jumpers to it which would render it impossible to get anything but RGB out of it later. I noticed there are 2 types of S-Video ports
Image
It seems you could use a standard 4 pin cable in a 7 pin port just fine so you could throw RGB on those extra pins and use the common ground but you need 1 more for C-SYNC. So my question is there some DIN-X that is compatible with the existing placement of S-Video pins but provides 4 additional ones? Then I think you could have a clean option for S-Video or RGB out of the standard kit, but would require a little rework to route that stuff there. I just figured since there was talk of a new version in the air a while back.

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Re: New PCB rev on the horizon

Post by cosam » Thu Jun 25, 2015 8:58 am

There is a variant of that connector but with two pins where the S-Video key usually goes. This would of course make it incompatible with S-Video but you could, using the jumpers you mentioned, offer a PCB that does both and leave it up to the builder to decide which they want. You could even use a completely different connector, maybe even borrow the pin-out from some other console, although the S-Video-like connector is more likely to have a similar pin footprint.

If you're thinking of using SCART, don't forget that you'll also need to supply at least +5V as different voltages on pins 8 and 16 are used to indicate activity (as well as aspect ratio) and to enable RGB mode. This need only cost you one pin though, as you can use a resistor in the SCART cable/plug itself to get the other.

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Re: New PCB rev on the horizon

Post by uze6666 » Mon Sep 14, 2015 2:22 am

Finally been working on the next revision of the uzebox PCB that integrates the ESP8266 and SPI RAM. I've basically added the content of the Uzenet module. I have to add another 3.3v regulator since the current one risk not being enough to power both the module and the sd card at the same time (we could try). I also connected PA7 to GPIO0 to allow upload of new firmware to the esp8266.

Here's the schematic and PCB layout. Please check it out for comments and obvious flaws, I'll order some prototypes this week. 8-)
f5.png
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Uzebox Game Console F5.pdf
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Artcfox
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Re: New PCB rev on the horizon

Post by Artcfox » Mon Sep 14, 2015 2:41 am

uze6666 wrote:Finally been working on the next revision of the uzebox PCB that integrates the ESP8266 and SPI RAM. I've basically added the content of the Uzenet module. I have to add another 3.3v regulator since the current one risk not being enough to power both the module and the sd card at the same time (we could try). I also connected PA7 to GPIO0 to allow upload of new firmware to the esp8266.

Here's the schematic and PCB layout. Please check it out for comments and obvious flaws, I'll order some prototypes this week. 8-)
f5.png
Uzebox Game Console F5.pdf
I've been meaning to ask you this since before I ordered my Uzebox kit. Why is the Luma trap notch filter tuned to the PAL frequency rather than NTSC? The schematic shown on page 15 the AD725 data sheet shows a 9 pF and an 18 pF capacitor connected in parallel for NTSC. If you leave out the 9 pF capacitor, then the notch filter is set to the PAL frequency. Shouldn't we be using a 27 pF capacitor there instead of the 18 pF that the kit currently ships with?

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uze6666
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Re: New PCB rev on the horizon

Post by uze6666 » Mon Sep 14, 2015 3:31 am

Artcfox wrote:
uze6666 wrote:Finally been working on the next revision of the uzebox PCB that integrates the ESP8266 and SPI RAM. I've basically added the content of the Uzenet module. I have to add another 3.3v regulator since the current one risk not being enough to power both the module and the sd card at the same time (we could try). I also connected PA7 to GPIO0 to allow upload of new firmware to the esp8266.

Here's the schematic and PCB layout. Please check it out for comments and obvious flaws, I'll order some prototypes this week. 8-)
f5.png
Uzebox Game Console F5.pdf
I've been meaning to ask you this since before I ordered my Uzebox kit. Why is the Luma trap notch filter tuned to the PAL frequency rather than NTSC? The schematic shown on page 15 the AD725 data sheet shows a 9 pF and an 18 pF capacitor connected in parallel for NTSC. If you leave out the 9 pF capacitor, then the notch filter is set to the PAL frequency. Shouldn't we be using a 27 pF capacitor there instead of the 18 pF that the kit currently ships with?
Initially I didn't put the luma trap and after Clay Cowgill made the AVCore, I blindly followed his schematic since he was the "real" engineer! That said, seems you are right, it's tuned to PAL. :? No wonder I never was too impressed with the luma trap. I'll order some 27pf to see how it looks.

Nice catch! :)

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