Because he's using this one on a 17mm board where there isn't room for a huge electrolytic cap. We know that it can function from the stock 105C cap., so it should be able to function here as well.
The 470uF/16v on the SRK driver is only for noise reduction, it shouldn't be needed for the MCU to function (but for some reason, it looks like it is letting the MCU work right, because the little 10uF/16v doesn't seem to be enough).
Ah…and just did a SMD 0805 search on digikey…largest SMD is 47μF
Well…that cap could be storing enough energy to keep the MCU alive at 470μF, opening up that huge MOSFET more than likely causes large voltage sag and drops the power below the MCU voltage range causing it to go all squiffy
But why does it work when you stick the same FET onto a 105C, using all the 105C's original parts? Is it possible the original cap isn't 10uF? There's nothing different about the new PCB, I've checked everything until I'm crosseyed.
Also there's nothing higher than 10uF in 0805 & X7R. 15 & 22uF 0805s only exist in JB, X5R, & X6S.
Is there any difference in the firmware between working and non working drivers?
Take a break, attack it from a different direction in a bit man
At some point for me it comes down to a fresh look after a good nights sleep. Or a big hammer and then a good nights sleep and fresh parts in the morning.
Nope, exact same build of luxdrv I used on the Nanjg-092 boards, same batch file with the same fuses and everything.
Try to add a cap directly to the Vcc of the MCU ( pin 8 ) and see if this can help.
It works properly with STAR v1.1 clicky version. luxdrv still didn't work even with a second 10uF in parallel.
I really have no clue what is going on.
And, I certainly know the value of a strategically-wielded hammer...
|(
Does STAR_mom V1.0 work on it?
is the PWM compile different from STAR V1.1 than luxdrv?
To-morrow will be a better day.
If the code is not an issue then is it possible for it to be corrupted during the flashing process? What I mean is, Is the flashing process foolproof. If the hardware is right and the traces are right and the soldering is right then where else can you look? Could it be a faulty mcu even?
If it works with one, but not the other, it’s not the hardware
And when flashing, it writes, then reads, to verify…if there is a problem it will tell you
Could it be a layout issue? I mean everything is connected correctly, but perhaps the comparatively longer traces (given the size of the board) required to get everything on the PCB are screwing something up?
I have even done an A-B-A test, luxdrv (no worky), STAR v1.1 (worky), back to luxdrv (no worky again). I re-reflashed an older Nanjg-092 driver that's been running the same build of luxdrv, and it still worked just the same as it did before. So, that build of luxdrv works on the 105C board+FET, but not on the new board.
I just browsed over the the last pages, so I didn’t get all details, but: is it right that that reset pin on the attiny is floating?
If yes, please try tying it to vcc with a 4.7k …10k resistor. That can easily cause such strange behaviour.
The thing is every board I have ever created with an ATINY chip (13 or 25 for me) has been setup exactly the same way. I have never experienced any of the problems that are being described here. Not saying it's right or wrong, just saying it's weird that Dale/Comfy are having issues. Happy to pass my BRD files onto anyone who wants to double check my work; it's entirely possible that I've made some stupid mistake.
- Matt