Hi there,
Hope it's OK to ask this here, otherwise let me know where is a better place...
I have developed an Arduino clone and using a typical ATmega16U2 based design for the USB-2-Serial part in the schematic. I can successfully DFU-program this with a .hex file (using one of the standard files for Arduino Mega or Uno rev 3), but when I reset everything and try to open the serial monitor I get garbage and when I try to send information from the Serial monitor, it gets passed on to the MCU after the ATmega16U2 at 1/8 of the selected serial speed (checked with Oscilloscope).
For instance: I open the serial monitor, set it to 115200 (the speed which I know the MCU is communicating at), I put my oscilloscope on RX and TX between the MCU and the ATmega16U2 and verify that I see 115200 baud communicate from the MCU. On the serial monitor I see only garbage though and when I send a few letters back to the MCU I see them on the RX line as roughly 14600 baud, 8 times less than then 115200 baud I was expecting.
Does anyone know what could cause this behaviour?