Great, doing a very quick test I can see what looks like correct signals output from the pins with my logic analyzer, I will report after doing a full test.

Thanks, however this is for the C3, I'm looking at the S3 and in the TRM the only signal numbers documented are usb_jtag_tdo_bridge (as an input, seems strange ?) and usb_jtag_trst. Do you know if the other signals are missing from the documentation ? Or if it's just not possible to route them on th...

I understand from the TRM that it should be possible to use the USB JTAG controller as a bridge to an external device by setting this register : USB_SERIAL_JTAG_USB_JTAG_BRIDGE_EN Set this bit usb_jtag, the connection between usb_jtag and internal JTAG is disconnected, and MTMS, MTDI, MTCK are outpu...