SPRUJF2A March 2026 – March 2026 AM13E23019
In the event that a device was configured by software to enter SHUTDOWN mode, and a debug probe is then connected to the SWJ-DP pins with SWCLKTCK active, wakeup logic triggers an exit from SHUTDOWN mode and cause a BOR. A debug connection can then be established to the DEBUGSS after the BOR completes. Please refer to Section 33.1.2.2 for additional details.
For secure applications, the software can be made aware of a debug connection by utilizing the DEBUGSS PWRUPIFG interrupt. When the debug probe is disconnected and the connection is lost, the PWRDWNIFG interrupt is asserted.
Application software can disable the SWJ-DP interface in SYSCTL, freeing the IO to be used for GPIO functionality. Review Section 3.5.1.4 in SYSCTL for using the debug pins for additional functionality other than JTAG/SWD. Once software disables debug functionality, it is not possible to re-enable it other than by triggering a POR. A POR will automatically re-enable the debug functionality and put the debug pins into JTAG/SWD mode with internal pullup/pulldown resistors enabled. To re-gain debug access to a device which contains software that disables the JTAG/SWD pins at startup, the device needs to be held in a reset state with the NRST pin during a POR. This will prevent the application software from starting and will allow the debug probe to gain access to the device, at which point a mass erase DSSM command can be sent from the integrated development environment to the device by the debug probe to remove the application software which is disabling the JTAG/SWD pins.