Today I joined the many who have issues to program an Arduino Pro Mini or, like in my case, a clone thereof. The error message very many people seem to get is
stk500_recv(): programmer not responding
There is an awful lot of stuff on the web how to solve this and I have tried to compile them in a list for others so that they can check:
- Programmer’s driver not installed on PC
- Arduino does not have a bootloader installed
- Arduino has other CPU compared to how it was sold
- Speed of serial port does not match with what Arduino expects
- USB-to-serial adapter has no DTR line
- RX and TX line labels mixed up on the board
- Faulty USB-to-serial converter (brand new CP2102 in my case)
In my case, however, it was even worse. Several of my clone board’s header connections were actually not connected! And among them was TX, so the error message was quite right.
What I did was download the datasheet from Atmel, identify my pin configuration from page 3, and start measuring connections. What I found was that TX on the six-pin header was not connected properly, while it was ok on the twelve-pin header. Also, GND was not connected on the bottom twelve-pin header.
Update Jan 06, 2017: The not connected GND pin was actually my own (soldering) fault.