The device supports ETM and ITM trace.
Trace data from the ETM and the ITM is sent to an external debugger via a 4-bit wide parallel trace port (TPIU) on pins TRACEDATA0 through TRACEDATA3 and TRACECLK.
In addition to parallel trace, the TPIU supports serial trace via the serial wire output (SWO) trace protocol. Parallel and serial trace cannot be used at the same time. ETM trace is supported in Parallel trace mode only, while both parallel and Serial trace modes support the ITM trace. For details on how to use the trace capabilities, see the debug documentation of your IDE.
TPIU's dedicated trace pins are multiplexed with GPIOs. SWO and TRACEDATA0 use the same GPIO. Trace is limited to dedicated pins. See Pin assignments for more information.
Trace speed is configured in the register TRACEPORTSPEED (Retained). The speed of the trace pins depends on the drive setting of the GPIOs that the trace pins are multiplexed with. The drive setting is configured using the DRIVE field of the GPIO register PIN_CNF[n] (n=0..31) (Retained).
Only drive settings S0S1, H0H1, and E0E1 should be used for debugging. S0S1 is the default drive at reset. If parallel or serial trace port signals are not fast enough in the debugging conditions, all GPIOs in use for tracing should be set to high drive (H0H1), or extra high drive (E0E1) for the fastest trace port speeds. Ensure that the drive setting of the GPIOs are not overwritten by software during the debugging session.
In addition to DRIVE, the GPIO pin must be assigned to trace and debug (TND), using the MCUSEL field of the the PIN_CNF register. When pins are assigned to TND, these GPIOs are output-only, and other functionality of the pins is disabled.