I know AtomicZombie a little, I talked to him a few times. But I didn't know that he was working to a similar project! Really strange, two persons at the same time, working on similar project. Kind of funny!
Seen your hello on AVRFreaks and decided to drop in here.
You have made some amazing progress on your project since we last talked on AVRFreaks.
Yeah, it is so cool that we have almost done the exact same things over the last year. In fact, I had just finished a VGA system as well right before trying to bitbang the NTSC color version. I guess us VideoFreaks all think alike because when I was doing a retro system years ago, the amazing UzeBox had just been release only days after I posted my project on AVRFreaks. It must be some kind of virus that drives us!
Wow, there is a lot of great info here, and this is a great community. I should have peeked in here earlier, but when you are up until 3:00 am counting cycles, who has the time!?
I will have to post my XMega VGA project soon so we can compare work. I see you did the same 8xtimer technique I did, creating an automatic 8 bit counter. I found that the timers had a 2-5ns phase error as well, but did find a way to correct this. Instead of using a 245 or 244 as an output buffer, use a 373 latch, and control LE on the last cycle so that all addresses are put back into sync. This works perfectly. You can also use the 373 OE as a blanking pin.
I have another system that uses 8 timers and has only 1 extra chip (the SRAM) and it manages 420x480 resolution using the internal PLL up to 64MHz. I hope to find enough time soon to detail my Vixen project on http://www.avrcade.com
, and I will then post all of my XMega VGA projects as well. We should collaborate on a project one day, I think we have the same hard-wired brains!
The Vixen project was a fun challenge. I sat down one free weekend and decided I would find a way to push out 256 NTSC colors without any external hardware. it took some careful PWM and cycle counting, but it turned out very well. The video is even more crisp than the AD724 version I was working on earlier. I did get 150x100 (dual buffered) resolution out of an XMega384, and although this is low, it looks great on a retro set. The 4 channel stereo sample mixer was an added bonus thanks to having so much free time on each line. Now doing some 3D routines and compression stuff.
Anyhow, great work! I look forward to seeing your progress and will bug you for some more details when I get my AVRCade site up and running. I want to profile every working AVR video or sound project I can find and try to make the site a hub for video freaks like us. I have about 20 tutorials to post (including some of my old LucidScience work), and hope it will inspire others to jump in and push these great AVRs to their limits. You will get a kick out of my bit banged color NTSC video system running on an 8 pin ATTiny... color pong with stereo sound!
I am under the gun to complete my AVR projects and get the site up and running because in a few months I switch to bike building and don't do much electronic work. If only a day was twice as long!
I would also like to send greetings to UZE666 and say thanks for your work. I know how much time and effort it takes to do these projects and then create these tutorials..... respect!