So I spent hours today trying to figure this out.

It programs ok, appears to run programs correctly, e.g. the ASCII table example, but the data that shows up in the Serial monitor window is just garbage.

When I hook my scope up to the serial pins, I see valid data. It's a SmartScope (lab-nation.com) so it has a serial data decoder built in. That seems to see valid data. But the data returned to the PC is still garbage. I ran it all the way down to 300 baud without any change. I tried using RealTerm, it also gets garbage. Removed the prototype board, no change.

It's as if the clock in the USB adapter is off, but if that were the case, it wouldn't program, right? And it does program, at 57,600 no issues.

Same PC programs the same sketch into a standard Arduino Uno and gets the correct values back.

I'm stuck. Any ideas?

[does]

We purchased another batch, and we still had the same problem. The serial data coming back from the board is garbage. This is just the standard AnalogReadSerial program. The very first example under "Basics"

Problem turned out to be a bad setting in the IDE, totally my fault, but in classic form, I'm going to blame your documentation... I mean suggest an improvement to your docs. Your getting started tutorial
https://tinycircuits.com/blogs/learn/124803655-tinyduino-setup-tutorial
does make mention of the cause of the problem, in one line which was not clear to me:
"Remember, the TinyDuino is 8MHz, not 16MHz!"

I didn't understand that, because there is no mention of a different speed in the selection of the Arduino Pro or Pro Mini board in the IDE. It's on a second item in the Tools menu which only appears after selecting the board; it's on the processor menu. I never even noticed it, until I was showing my favorite rubber ducky how I was getting the error.


I would really suggest showing that menu selection as a separate sketch in your documentation if only for people like me who are complete idiots... I mean, sometimes miss things like that.