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Cortex Debug (10-pin)

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.

10-pin Pinout Diagram

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/Output)
  • TDO is SWO (Serial Wire trace Output)
Signal Connects to...
SWDIO Data I/O pin. Use 100K Ohm pull-up resistor to VCC.
SWO Optional trace output pin.
SWCLK 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.

Note

  • Refer to Connectors for additional information.
  • Usually, devices do not include pull-up or pull-down resistors on JTAG nor SW pins. Resistors should be added externally onto the board. However, do not add resistors when the device includes them already.
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