The Cortex Debug (10-pin) connector supports both JTAG and Serial Wire signals. For Cortex-M processor-based devices, you can configure the debugger for either JTAG or Serial Wire mode. JTAG Signals Signal Connects to... TMS Test Mode State pin — Use 100K Ohm pull-up resistor to VCC. TDO Test Data Out pin. TDI Test Data In pin — Use 100K Ohm pull-up resistor to VCC. TCLK Test CLocK pin — Use 100K Ohm pull-down resistor to GND. VCC Positive Supply Voltage — Power supply for JTAG interface drivers. GND Digital ground. nRESET nRESET pin — Connect this pin to the (active low) reset input of the target CPU. Use 100K Ohm pull-up resistor to VCC. This is an open-collector/open-drain output. Serial Wire Signals The Serial Wire mode is a different operating mode for the JTAG port, where only two pins are used for the communication. A third pin can be used optionally to trace data. JTAG pins and SW pins are shared. TCLK is SWCLK (Serial Wire Clock) TMS is SWDIO (Serial Wire debug Data Input/Outp