Hi I'm trying to use the USBavr with the promini 3.3v. The programmer is one of those really using 5v or 3.3v levels. From all my knowledge I should connect the VCC pin, but programmig just works if I connect RAW to the programmers VCC. If I don't connect the programmers VCC but use external source for the pro mini it doesn't work at all. All in all the 3.3v seems to be unreliable. If I program using 5v levels it works better. though I 've got to disconnect some 3.3v modules ...
Does that make sense, or is my programmer crap? Or do you've got any tips there?
thanks Markus
First, we need more information.
It would be nice to know exactly what kind of programmer you have (link to the seller's website or photo).
Show your wiring diagram or a good photo of the connections.
There is information that such programmers do not always work correctly with 3.3V, and sometimes the 5V and 3.3V labels are reversed.
Hi, did some further testing and Google. I think it is exactly the 3.3 vs 5v problem. it's not really doing 3.3v therfore running fine with 5v.
This board has an ATmega328P and can be supplied with 5V.
Pro Mini (Atmega 168, 3.3V/8MHz)
The difference is that the 3.3V board has an 8 MHz crystal, and the 5V board 16 MHz one.
I am using USB-UART converter with CH340E to program Pro Mini 5V 16 MHz. Works great.
Such as https://j.lnwfile.com/_/j/_raw/in/rp/xg.jpg
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