Regarding multiple channels:
There is an alternative to PWM if you need more channels: BAM (Bit Angle Modulation), 8 channels are easily doable (if you have the pins). I did some tests last year and it worked out quite well. It’s a bit tricky to program and I wouldn’t choose this method if I needed smooth ramping with 7135 at low levels.
Regarding the reset pin:
if you use this pin you don’t need expensive programmers for further reprogramming. I built a cheap fuse resetter with this instructions: http://www.rickety.us/2010/03/arduino-avr-high-voltage-serial-programmer/
I used a arduino nano and a cheap MT3608 boost converter for the 12 V ouput.
I'm not saying only two are possible. However, only 3 are possible using the hardware waveform generators. There are 4 output compare registers but two of them have waveform generators that attach to the same pins.
Anyway, yes, I've figured out how to get 4 in principle. You need to leave the 4th compare register detached from the pin, and enable its(the register not the pin) interrupt, and use the interrupt to bit-bang the OTC pin. In phase mode you need to keep track of ups and downs. (why are we using phase-correct mode though?)
It's not too bad really. The datasheet recommends against it because it will keep the CPU busy. On the other hand, what else is this CPU busy doing hunh? It's not like we're going to connect these lights to SETI are we? I shouldn't ask.
Sigh.. the tripple version was clearly whipped up a littel quickly to work and was no longer compatible with single and double versions anyway, so I've started cleaning that all up and adding capability for a fourth channel too. It does mean ramps don't have nice names anymore but are just RAMP_PWM1 ... etc, but calling it 7135s just inhibits keeping the code flexible.
I've also simplified the defines to maybe make configuring creative driver setups a bit easier. I don't promise TK would approve of all the changes. Maybe someday I'll even finish something.
Oh someone asked about frequency. As far as I can tell bistro tripple is running at CPU frequency. The PWM ramps up to 255, but the 7135 and 7135s are in phase mode so it ramps up and down, so that's a frequency of 8Mhz/500 so 16khz. The FET doesn't have a phase correct option and appears to me to be running at 32 khz! Unless I'm missing something.
but it actually does save a few bytes over using globals. It kind of just went from one to two, and then someone hacked a third on, and now it's kind of silly.
And by the way, things are bit broken now. I said I implemented it, but I've done a bunch of "clean" up and reorganizing and who knows how long it will take me to recover from that. I haven't even tried to run it yet. I already know of one thing I broke (a feature that I added though), but I'm not going backwards. I'll twiddle at getting it all in shape as I get time.
:FACEPALM: It ended up being just a dumb mistake. After all that I deleted it. I just didn't have optimization on at the time, doh.
Some days are like that programming. You know like when waste a bunch of time just to figure out the program you're running is in a different directory than the one you're compiling, which explains why the last 10 ways you tried to fix it didn't work. I'm pretty sure anyone who's programmed much has done that one before... or maybe it's just me.
I can vouch for that, for sure.... Was gonna ask bout the S optimize setting, but thought that was little insulting . Anything one could get wrong, I've done, I'm sure. All a matter of how fast you can figure it out. Many times I come in the next morning and it's obvious, staring me in the face.
So here's a new one. Vcc ADC reading seems to mess with the light a bit.
I did of bunch of recent changes without testing, just getting the code organized, surprised things mostly work still, but they seem to. Except the light had a pule, a heartbeat. After burning through another 20 flashes on this poor attiny's life it boiled down to the adc being on and set to the Vcc reference, and having changed the timing of things I noticed now when not before. In fact I intentionally was cycling the ADC on longer between voltage and thermal mode to stabilize readings, but that's the heartbeat. Of course ADC_on was the last thing I suspected. It seems that an adc reference on the Vcc pin is disturbing the electronics and dims (we don't want dim) the light a little.
It's a full single 7135 mode, no PWM. Being a regulator I'd hope it wouldn't be too sensitive to a little voltage fluctuation. I have found these things are pretty finicky,very easy to break entirely. Maybe I should replace the 7135 and see what happens.
I hope that I’am in the right thread. Does anybody get the lvp working for 6V configuration with 36k/4,7k Resistors? For example with blf-a6 firmware. I would be glad to see the code. Thank you guys!
. Anything one could get wrong, I've done, I'm sure. All a matter of how fast you can figure it out. Many times I come in the next morning and it's obvious, staring me in the face.