Category:Cortex Debug

Jtag

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

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.

Reference

• https://www.keil.com/support/man/docs/ulinkpro/ulinkpro_hw_if_jtag10.htm