Re: ZVG firmware / the future of ZVG

hmmmm Raspberry Pi

www.raspberrypi.org/

----- Original Message -----
From: "Clay Cowgill" <c.cowgill@comcast.net>
To: <vectorlist@vectorlist.org>
Sent: Friday, April 20, 2012 9:24 PM
Subject: RE: VECTOR: ZVG firmware / the future of ZVG

>> My version would use an ARM processor with built in 12 bit
>> DACs, 2 to 4
>> 16 bit timers (based on the programability of the start and
>> stop times of the timers).
>
> Yep! Although I'm just using the internal 12 bit DACs and spare GPIO's
> for
> the brightness control with a R2R type DAC. Our board is specifically a
> plug-n-play for Asteroids/AstDlx (or other cabs with an adapter).
>
> Nice thing on the modern ARMs is that their timer counter peripherals
> generally run at up to the full bus clock and with 32 bit counters your
> 'draw timer' still won't overflow even from a really fast clock. (We're
> using 72MHz, for example. So even hundreds of microseconds won't overflow
> and you still get a stupid amount of timing resolution.)
>
>> You should be able to get all the power you need from the USB
>> interface, you'd need a 5V to +/- 15V switcher, but not a lot
>> of current. And, what the hell, throw in a TCP/IP port to
>> allow the generator to be run remotely from any computer on the net.
>
> I only use the USB power to run the digital stuff for programming the
> board
> from a PC (ie, plug the board in to PC to load games and emulator updates
> away from the cabinet and plug it back in to play). For development I
> have
> one of those little 5->+/-15 DC/DC SIPs on the board, but since I want to
> just plug into the original power harness I'm making my own +/-12V
> 'analog'
> rails from the transformer supplies anyway. (No sense in paying extra for
> DC/DC since the raw components are already there and our current
> requirements are miniscule.)
>
>> With a 100MHz to 300MHz clock, you could easily add an
>> emulator to the ARM. You could have a full Cinematronics PCB
>> replacement board the size of the ZVG, with all the games built in.
>
> Yes, yes you can. ...and it can play anything else with 'compatible'
> controls too. :-) ...and even just 72MHz of ARM can push a metric assload
> of vectors around with native game code. ;-)
>
> Even with CPU cores in C you don't really need anywhere near that kind of
> clock speed (with a good programmer and smart compiler anyway :-). (Or is
> that smart programmer and good compiler? :-) Our old emulation board for
> Arcadeshop was just a 66MHz ARM7TDMI and we could run Asteroids/BZ/etc.
> just
> fine on it with an assembly 6502 core. (That was including rasterizing
> and
> losing about ~20% of the CPU to system overhead!) A <100MHz ARM is quite
> capable!
>
>> I'm going to publish the math used to generate these timing
>> tables, and the proper ending DAC values, along with the
>> code. It's the most important part of the generator.
>> Publishing the code without it wouldn't be that much more
>> helpful than a binary image.
>>
>> Let me know if you or Neil, would like to look at it before I
>> get the licensing worked out, and I'll send you the info.
>
> Actually, that is exactly what I have been putting off doing for a while
> now, so yeah-- I'd love to take a look at what you did because otherwise I
> was going to be doing a lot of brute-forcing my way through things and
> building big lookup tables and I was *not* looking forward to it. ;-) That
> is *literally* the next thing I was going to work on. I'd run out of
> other
> stuff to check out and that was the last big 'to-do' item...
>
> (So, massive Thanks In Advance for any help there-- hit me at
> c.cowgill@comcast.net whenever!)
>
> -Clay
>
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Received on Fri Apr 20 20:30:47 2012