AVGA - video for the rest of us?

Bramblefax · Post by **Bramblefax** » Thu Aug 13, 2009 2:30 am

http://avga.prometheus4.com/
This looks very cool. Someone's done all the tedious parts of writing an entirely interrupt-based software video generator for sub-$5 Atmel AVRs (plus the cost of a programmer), making it possible to add one-chip video to any project. Once I get my Hunley up and running, this will be the first thing on its upgrade list.

Nightmaretony · Post by **Nightmaretony** » Thu Aug 13, 2009 5:08 pm

Interesting. I was looking at the VGA based on an XC108 CPLD but this one will prove interesting for game work (the CPLD version is a straight bit map setup that you use an external processor)

http://elm-chan.org/works/crtc/report.html

BigEd · Post by **BigEd** » Fri Aug 14, 2009 7:09 pm

The AVR design is interesting - although to me it looks more like a video-capable system than a video peripheral. I get the impression there are some free ports, so one could perhaps drive it that way.

(It's tile based, you're expected to have most tile data in ROM, but copy to RAM and modify, so far as I can tell. But it drives video with just a handful of resistors and the AVR in a DIP. The AVR is run at 20MHz, and puts pixel data out in real time, leaving 3MHz of computational power free for other use.)

I like the way the website is done in 4 bits per pixel.

On a similiar note, has anyone read Racing the Beam, about programming the atari VCS? Or indeed tried to program in that way?

BitWise · Post by **BitWise** » Fri Aug 14, 2009 8:03 pm

BigEd wrote:

The AVR design is interesting - although to me it looks more like a video-capable system than a video peripheral. I get the impression there are some free ports, so one could perhaps drive it that way.

(It's tile based, you're expected to have most tile data in ROM, but copy to RAM and modify, so far as I can tell. But it drives video with just a handful of resistors and the AVR in a DIP. The AVR is run at 20MHz, and puts pixel data out in real time, leaving 3MHz of computational power free for other use.)

I like the way the website is done in 4 bits per pixel.

On a similiar note, has anyone read Racing the Beam, about programming the atari VCS? Or indeed tried to program in that way?

I've been working on something similar with a Microchip PIC. Less MIPS so I'm only getting 40x25 characters (8x8 tiles) in monochrome @ 11Mhz. Was going to use it as a simple terminal emulation.

I had a go at 2600 programming a while back. Timing is everything and I didn't have the patience for it.

Bramblefax · Post by **Bramblefax** » Fri Aug 14, 2009 11:44 pm

Indeed. It's got most of portC open if you don't want the "controller" buttons, and all of portA. The C API is really pretty remarkably clean and complete, for uC code(I'm used to staring at pages of assembly rather than prettified GNU C), but a 6502-facing interface for the complete capabilities of that API is probably not necessary. I've been thinking about what capabilities I would expose to my micro, and it would surely be some some subset that included the windowing capabilities and a sub-character scroll engine, but probably not all of the overlay and sprite capabilities. Anyway, turning it into a color version of a TV-typewriter with a custom character map would seem nearly trivial, and that may indeed end up being all that I do with it initially.

Heck, I could have both. With video this cheap and processor unintensive, why not have a dual screen system, one text terminal and one for windowed video graphics?

kc5tja · Post by **kc5tja** » Sun Aug 16, 2009 5:57 am

BigEd wrote:

On a similiar note, has anyone read url=http://www.atariage.com/forums/index.php?showtopic=138019]Racing the Beam, about programming the atari VCS? Or indeed tried to program in that way?

Yes -- I've written several small applications that fit entirely inside a SeaForth 24A chip, one of which was a fairly simple video stopwatch/clock. Although with sufficient effort I could have gotten numbers to display, I instead chose for the more simplistic quasi-analog display of "needles" traversing a field to indicate time.

It was a lot of fun, and yes, it took a lot of patience. But, it was quite doable.

A video of my FIG Forth-Day presentation is somewhere on the Internet, but I'll be damned if I can find it again.

yzoer · Post by **yzoer** » Thu Oct 29, 2009 9:46 pm

Little late but...

I've been working on XMOS' XC-1 multicore chip and did a tile-based video system. In case anyone's interested, here's a clip on YouTube.

http://www.youtube.com/watch?v=A5eU8pHpy-c

Yvo

P.S. Now also does NTSC

Nightmaretony · Post by **Nightmaretony** » Thu Oct 29, 2009 10:12 pm

KEWL. I just heard of the XC-1 for the first time in my life reading a trade magazine at work during lunch. Might be the future gig

ChuckT · Post by **ChuckT** » Sun Nov 01, 2009 3:33 am

Is this the same chip in the Fuzebox?

http://www.ladyada.net/make/fuzebox/

TMorita · Post by **TMorita** » Wed Nov 18, 2009 7:57 am

yzoer wrote:

Little late but...

I've been working on XMOS' XC-1 multicore chip and did a tile-based video system. In case anyone's interested, here's a clip on YouTube.

http://www.youtube.com/watch?v=A5eU8pHpy-c

Yvo

P.S. Now also does NTSC

The company I'm working at now has a similar product, except with 12 threads instead of 8:

http://www.ubicom.com/products/mmprocessors.php

If you want samples, I may be able to bug some people and get a few for you.

It would be nice to have a subforum on here for non-6502 homebrew systems...there seems to be a lot of interesting in building systems with non-6502 chips.

Toshi

ChuckT · Post by **ChuckT** » Wed Nov 18, 2009 1:40 pm

TMorita wrote:

The company I'm working at now has a similar product, except with 12 threads instead of 8:

http://www.ubicom.com/products/mmprocessors.php

If you want samples, I may be able to bug some people and get a few for you.

It would be nice to have a subforum on here for non-6502 homebrew systems...there seems to be a lot of interesting in building systems with non-6502 chips.

Toshi

I'm interested in the video chip and I'm interested in hearing more. I would like to see some single board computers as I would like a computer to advance what we had on the Commodore 64 or Apple IIe and I'm interested in even getting involved. Please email me so I can have more information because I will want to breadboard the chip.

I know where you can get some free forums but I don't have a method to drive people to the forums. I think forums with people helping people make the chips easy is a way to further involvement and homebrew development.

ChuckT · Post by **ChuckT** » Mon Apr 19, 2010 3:37 am

Ubicom wouldn't respond to me.

I found the chip. They are using a cheaper Sparkfun board instead of the Xmos version which doesn't really lower the price:

http://www.sparkfun.com/commerce/produc ... ts_id=9428

The more expensive board is sold by XMOS and it has more cores and more mips.

https://www.xmos.com/products/developme ... opment-kit

Xmos has three or four versions and one uses USB while one or more uses a JTAG interface. I'm not sure why people are opting for the Sparkfun board when they can get more (cores) features for the same price without having to buy the JTAG connector.

Some of the users on Xcores.org say that it is horrible with video but there is a core out there that lets you use two backgrounds and 32 sprites using a graphics engine that is written by someone. They are having a hard time to get the right oscillator to make NTSC.

http://zuzebox.wordpress.com/category/x-one/

Dimitri · Post by **Dimitri** » Tue Apr 20, 2010 1:19 am

I have decided to go with a "off the shelf" VGA solution instead of a LCD for my monster, so AVR is the way to go for me. I mention this because there are many of these projects online that serially allow printf commands to go to it from another microcontroller.

They would save development time on any project with a spare UART port.

Dimitri

yzoer · Post by **yzoer** » Tue Jan 11, 2011 7:35 pm

ChuckT wrote:

Ubicom wouldn't respond to me.

Some of the users on Xcores.org say that it is horrible with video but there is a core out there that lets you use two backgrounds and 32 sprites using a graphics engine that is written by someone. They are having a hard time to get the right oscillator to make NTSC.

http://zuzebox.wordpress.com/category/x-one/

Hi There!

The NTSC version has been out there for a while and the source is available on xcores.org if you're interested. It's hard to find a (non-smt) oscillator for PAL unfortunately..

ChuckT · Post by **ChuckT** » Tue Jan 11, 2011 9:02 pm

yzoer wrote:

ChuckT wrote:

The NTSC version has been out there for a while and the source is available on xcores.org if you're interested. It's hard to find a (non-smt) oscillator for PAL unfortunately..

I already came across two companies that will make you a crystal but I haven't looked into it because I don't own the board. I suppose that would be the way to go.

Here is my post which lists these two sites:

www.quartslab.com/
http://www.icmfg.com/

viewtopic.php?t=1576&highlight=crystals