I’m programming an application on SAMR34-XPRO board, and everything is fine until I start using stdio over USB CDC ACM. Turning the radio on, even in listen mode, resets the USB connection.
The problem can be reproduced even with the default sx127x test:
BOARD=samr34-xpro USEMODULE=stdio_cdc_acm make -C tests/driver_sx127x/ flash
Disconnect EDBG, attach to TARGET USB, and proceed with the interactive test. All commands that change the radio mode reset the USB connection - even
random. Here is an excerpt of the relevant messages in dmesg:
[45958.340012] cdc_acm 1-1.3.2:1.0: ttyACM0: USB ACM device [45969.993189] usb 1-1.3.2: USB disconnect, device number 74 [45969.995472] cdc_acm 1-1.3.2:1.0: failed to set dtr/rts
If the EDBG port is left connected, even with a USB battery, then the problem disappears.
It looks like some power issue, but the radio in itself should not be that power hungry. Tried with
CFLAGS=-DCONFIG_USB_MAX_POWER=500 but it makes no difference.
Anyone has hints about how to further debug the root cause?
Thanks a lot in advance,