diymore5pcs Pro Mini ATmega328P 3.3V 8M Module Board with Crystal Oscillator Pins Replace ATmega128

While I've not had a lot of time with these Pro Minis, I have come across a problem that will have you pulling your hair out. After soldering the headers on and connecting the devices to my desktop computer via a USB-TTL adapter, I ran a simple program to output data to the console via the serial interface. I got nothing but garbage. I checked my Arduino IDE settings and they were correct for a Pro Mini using 3.3 volts running at 8 MHz with a 9600 baud rate. After the loss of much hair, I found that by changing the console baud rate to 4800, the serial interface worked. After that, I set the Arduino IDE to expect a 5 volt 16 MHz Pro Mini still at 9600 baud and found it communicated at 9600 Baud over serial. Apparently the internal boot code for the devices has a bad register setting for the clock that does not match the actual frequency of the resonator. The devices are certainly usable as is, but they are not exactly what was expected. I am going to try to reprogram the devices correctly.

Like - this suppliers 3.3V mini works with an arduino Uno as the FTD serial interface to a PC. Other suppliers don't. I suspect its how robust the interface is to the 5V logic coming from the Uno.Dislike - Nothing that I've encountered. Works like a champ.

These are so cool! I built and rc transmitter with one, a receiver with the other, and have 3 left. Arduino heaven!

Decent enough for the price. In order to upload I had to put a 100 nF cap between the DTR line of my programmer and the reset pin of the mini.

The voltage regulator on the board can not handle much more than 11V. Most other mini pro boards can use up to 16V.

I needed the 3.3v boards quickly, and these delivered.