#avr Logs

Aug 02 2019

12:01 AM steaktartaar: Thrashbarg: programmer arrived and is working fine :)
12:06 AM Thrashbarg: good hehe
12:23 AM steaktartaar: I'm looking into video output. I know about the libraries for composite out via software but I'm wondering how it works if I want to do it in hardware - I know that early micros used an IC with hardware video functions that mapped to memory, can you get something today that, say, outputs characters to composite?
12:23 AM steaktartaar: I'd be easier to search for if I knew the terminology
12:23 AM steaktartaar: a text-only VIC II?
12:29 AM steaktartaar: Google says "try the 1970s"
01:00 AM rue_mohr: there is a fellow here that made a vga video thing
02:18 AM KimK: steaktartaar: Do you mean old-school composite video? Do you want to build a circuit, or just get the video characters no matter how they got here? I might be able to help, depending on what you're doing.
02:37 AM steaktartaar: Right now I have a system with only a UART connection as IO. I want to hook it up to a TV, and I *kinda* know how to do it using pinouts & software from doing the same on an Arduino. So for this project I can probably do the same, but that would mean implementing everything in software.
02:39 AM steaktartaar: Plan B is to just hook up an old ARduino over serial and use the TVOut library, but that kinda defeats the point of learning new stuff
02:41 AM steaktartaar: essentially, this or an equivalent: https://en.wikipedia.org/wiki/Motorola_6847
02:52 AM KimK: Heh, long ago I did a project with the 6845 https://en.wikipedia.org/wiki/Motorola_6845 OK, so you'd be satisfied with the relatively chunky characters as described (implied?) in the table? And you're OK with old-school video only, not upgradeable to 1920x1080 (HD) or even 1280x720 (SD) video?
02:52 AM steaktartaar: absolutely
02:52 AM steaktartaar: my target is 80x24 text only monochrome
02:52 AM steaktartaar: and I'm willing to settle for 40x16
02:53 AM steaktartaar: 32x16 I mean
02:55 AM KimK: OK, then carry on, I don't have much advice for you. Well, maybe if you search eBay you could find a Chinese character generator box (or PCB) with "calculator keyboard" for old-school video characters, but I get the idea that you're looking for a project? OK, there you go.
02:55 AM steaktartaar: :)
02:55 AM steaktartaar: guess I'll just give it a go and see where I hit a brick wall
02:57 AM KimK: Yes, my project was 64x32, and that's about all you can cram onto an old-school CRT, RF modulators were not that great with, it really wanted a direct video connection.
02:58 AM KimK: And to get that high a res, it had to be interlaced, so there was a barely-perceptible 30Hz flicker as the lines alternated.
02:58 AM steaktartaar: the 6845 only does address translation?
03:00 AM KimK: I don't remember what all it did, but yes, you had to provide a lot of stuff to get it going. I found a broadcast quality video sync generator chip in a 16-pin DIP which helped, but good luck finding that anymore.
03:02 AM KimK: The video shift register was external for sure. Maybe Motorola still has an app note (AN-xxxx) online for the thing? Or at archive.org?
03:04 AM KimK: If your characters are bigger (and blockier looking?) you won't have the flicker problem, or will have trouble perceiving it anyway.
03:05 AM KimK: As I recall, the Apple II screen was 40x?? (16?24?) and it worked pretty well with RF modulators.
03:06 AM KimK: Somebody made an 80 column card for the Apple II, but then I'll bet you'd be back to monitors instead of "channel 4".
03:08 AM KimK: From everything you've said, so far I'm liking your "Plan B" Arduino deal the best, but that's just me.
03:18 AM KimK: Lately I had to add characters to livestreaming video, and eventually settled on OBS Studio https://obsproject.com/ So if you were going that way, I might have been more helpful, sorry. This guy is using the "Text GDI+" feature of OBS to add text (and with a color gradient, too): https://s14-eu5.startpage.com/cgi-bin/serveimage?url=https%3A%2F%2Fpub.rachni.com%2Fimg%2Fobs64_2017-08-03_20-09-46.png&sp=69045315d581ef09eb2b7bd9e55fe81a&ant
03:18 AM KimK: icache=817582
03:18 AM KimK: Oops, let me fix that breakage...
03:19 AM KimK: https://s14-eu5.startpage.com/cgi-bin/serveimage?url=https%3A%2F%2Fpub.rachni.com%2Fimg%2Fobs64_2017-08-03_20-09-46.png&sp=69045315d581ef09eb2b7bd9e55fe81a&anticache=817582
03:28 AM steaktartaar: I didn't know OBS did overlays
03:28 AM steaktartaar: learn something new every day
03:30 AM KimK: Yeah, but I don't know how you would control it from your serial port, scripts maybe? Maybe not, OBS Studio kind of expects a director.
03:33 AM KimK: I think you could set OBS to "old-school" picture sizes and then use some kind of aux VGA output and then VGA to composite converter box, that might be doable.
03:34 AM KimK: It would be odd for sure, but it might work.
03:35 AM KimK: Maybe somebody makes a PCI to composite video card that OBS could use?
02:22 PM [1]MrMobius is now known as MrMobius
08:07 PM FozzWorth: are interrupts generally ill-advised for detecting rotary encoders? I'm reading conflicting reports.
08:09 PM FozzWorth: I'm using external INT0 and 1 on a m328p for the rotary/switch and am at the point where I need to look at debouncing but figure I should ask before I get too far with it
11:54 PM day__ is now known as day