Harold, thanks for replying to both my posts. Basically, this is exactly what I am trying to do. I know I could just buy one, but depending on how long it takes me, I might be able to use it as a project for my final year of university. Anyway, I think this project is still far off. I don't have enough experience with the PIC to fully understand UART reception and the capture/compare module still confuses me to no end, even having read the data sheets numerous times. I hope that eventually I'd find some tutorial or something that will just make the light go on in my head. I know it's not that hard, I just think I'm missing something simple. To me it seems this project will be quite hard, because I'm dealing with two very time dependent things, and I have no control over either of them. It seems quite intimidating. I think I will try to build up my confidence with my transmitters, and look closer at Kelly Kohl's receiving code, then perhaps try to build some DMX controlled relays or the like. At least that way I don't have to deal with the AC cycle. In the meantime, do you have any suggestions for good UART and capture/compare tutorials? Once I get enough money, I hope to be able to by the Serial PIC'n book. Unfortunately, I don't have much money, so it could be awhile. Anyway, thanks for your help and advice. Josh joshy@mb.sympatico.ca Harold M Hallikainen wrote: > > Your project sounds like the Shoebox dimmer (DM406 and DM410) at > http://www.dovesystems.com . These are 4 channel dimmers. A 16c74 > receives DMX (and analog) and puts 4 channels of it in RAM (based on a > thumbwheel channel select switch). An interrupt is generated at zero > crossing from the power transformer secondary. The capture compare > register is in compare mode and generates an interrupt when it's time to > turn on a triac. The interrupt routine then figures out which triac to > turn on next and the time to turn it on (the timer is cleared at zero > cross). So, it CAN be done. That's a 16c74 at 16 MHz running 4 dimmers. > > Harold > > On Sun, 13 May 2001 01:12:49 -0500 Josh Koffman > writes: > > I'm thinking about a new project. Basically it will be a single > > channel > > DMX512 controlled dimmer. Well, single channel at first...dual or > > quad > > would be nice eventually...I have the i/o, but probably not the > > processor time. Anyway, DMX512 is a lighting control protocol. It is > > a > > serial async signal transmitted at 250kbps. I want to integrate a > > DMX > > reciever and a dimmer on a single 16f876. For dimming, at least to > > start, I will use a triac, and trigger it based on a time delay from > > the > > last zero crossing. For basic inputs I will have the differential > > line > > reciever, and the zero crossing detector. For outputs I will have > > just > > the triac trigger. There will be other things as well, to allow you > > to > > set the DMX channel number and such, but they aren't as important. > > So > > basically, I'll be dealing with two time intensive operations > > (recieving > > 250kbps serial stream, and triggering a triac 120 times a second). > > Will > > I have enough processor speed? I'm not really sure how to go about > > doing > > this. Thanks to work by Kelly Khols and Adam Davis, I know each task > > can > > be done on its own. The question is can they be intertwined on one > > processor? Would I use interrups for both? I haven't started to > > build or > > program because I can't quite get it clear in my mind. So far, the > > best > > solution I have thought up is to figure out how long it'll take me > > to > > receive a packet, and then figure out how many AC half cycles I can > > get > > in there. Then I set up a loop, dim for X number of half cycles, > > then > > empty the RX buffer. I know this probably isn't the best way though. > > Any > > help or ideas would be greatly appreciated. > > > > Thanks! > > > > Josh > > joshy@mb.sympatico.ca > > > > -- > > http://www.piclist.com hint: The list server can filter out > > subtopics > > (like ads or off topics) for you. See http://www.piclist.com/#topics > > > > > > ________________________________________________________________ > GET INTERNET ACCESS FROM JUNO! > Juno offers FREE or PREMIUM Internet access for less! > Join Juno today! For your FREE software, visit: > http://dl.www.juno.com/get/tagj. > > -- > http://www.piclist.com hint: The list server can filter out subtopics > (like ads or off topics) for you. See http://www.piclist.com/#topics -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics