4.2.3. JTAG and SWD interface

The external JTAG interface has four mandatory pins, tck, tms, tdi, and tdo, and an optional reset, ntrst. JTAG-DP and SW-DP also require a separate powerup reset, npotrst.

The external SWD interface requires two pins:

The block level interface has two pins for data and an output enable that must be used to drive a bidirectional pad for the external interface, and clock and reset signals. To enable sharing of the connector for either JTAG or SWD, connections must be made external to the SWJ-DP block. In particular, tms must be a bidirectional pin to support the bidirectional swdio pin in SWD mode.

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