I have been successfully using a USB-to-serial programmer based on the SILABS CP102 to program my Mini's under IDE 1.0.5 (on a Linux machine). I have installed IDE 1.6.4 and I now get the following error:
Sketch uses 17,432 bytes (60%) of program storage space. Maximum is 28,672 bytes.
Global variables use 1,159 bytes (56%) of dynamic memory, leaving 889 bytes for local variables. Maximum is 2,048 bytes.
avrdude: stk500_recv(): programmer is not responding
avrdude: stk500_getsync() attempt 1 of 10: not in sync: resp=0x00
avrdude: stk500_recv(): programmer is not responding
I get the error ten times and then:
avrdude: stk500_getsync() attempt 10 of 10: not in sync: resp=0x00
Problem uploading to board. See http://www.arduino.cc/en/Guide/Troubleshooting#upload for suggestions.
I checked that there is no connection to RXTX on the Mini, but I don't think that would cause the "avrdude: stk500_recv(): programmer is not responding" part of the error.
Update: I went back and loaded a different sketch, which compiles without error under 1.0.5, and I get the same error "programmer is not responding."
I don't think I have changed anything except reloading all the libraries in a new location, eg, not disturbing the libraries that 1.0.5 was installed with.
I have changed the hardware to a different (same model) programmer.
Update: Under IDE 1.6.3 on a Windows 8.1 laptop, I get the same "programmer not responding" error. I looked under device manager at the ports and I see the Silicon Labs 210X USB to UART (COM3) device. COM3 is selected in tools.
Can you retry the upload while manually resetting the board. You will need to reset the board right about the time that the IDE reports the size of the sketch.
Also, try a loopback test on the USB-TTL adapter to verify that it is working correctly. To perform the test on your adapter you only need to connect a jumper between Tx and Rx while sending some data to the COM port via the Serial monitor. You can do this with the Arduino disconnected and should see everything sent "echoed" inside the monitor if the device is working.
Thanks, the loopback test was a great hint--works perfectly.
But the upload is still no good. Reset (many times) didn't help. If it did work I think that would resolve the "not in sync" error, but not the "programmer not responding" error.
I looked closely at the programmer right after the compile was completed and the TXD LED flashed quickly 3 times, then after a long delay, flashed once (I think this is the second try, etc...). I don't see anything on the RXD LED.
This is a "common mode" error. It happens on two different IDE versions, with two different programmer boards, and on both Linux and Windows machines. I decided it had to be the cable, so I did a loopback test at the far end of the cable. That test works fine, too.
I am out of immediate ideas. I can't think of anything I have changed, except maybe attached (or re-attached) libraries. But if so, it wasn't done the same on both laptops, yet it's the same error
.