USB serial port garbage when the device resets

Question

When I reset a USB device that is connected via USB serial it starts printing garbage.

If I close out the serial monitor (using Arduino's serial console but should not matter) and reopen, clean text starts printing. Judging by the rate of transmission, the garbage is clearly caused by my device doing normal serial printing -- that is, it is not random garbage.

This is a homebrew USB serial device so the problem could very well be in there. In fact, I can very easily change the code in USB serial device, but cannot do the same for the serial terminal program :-), so would prefer if the solution was there.

No, this is not an incorrect baud or parity setting so please don't suggest it! :-)

Thanks for any help/ideas!

Answer 1

Is it printing garbage even when nothing is being (intentionally) transmitted? If so, there is a hardware problem. Either it resets into a "break" state, or it is jabbering.

If it happens only when data is written through it, then, when the device resets, what serial settings does it default to? Almost certainly this is caused by a speed/data bits/stop bits problem.