Serial Wire Debug (SWD) support with UDE® debugger

The Serial Wire Debug (SWD) interface or Serial Wire Debug Port (SW-DP) is one of the features of the debug and trace technology Arm CoreSight™ for Cortex. First implementations of SWD are realized in the derivatives of the Cortex-M3 core Stellaris of Luminary Micro (now Texas Instruments) and in the derivatives of the STM32 family by STMicroelectronics. The known JTAG Debug Port (JTAG-DP) is supported furthermore. Both debug ports, the SWD and the alternative JTAG debug port can be combined to the Serial Wire JTAG Debug Port (SWJ-DP), the CoreSight standard port.

When using SWD, the TDO signal can provide trace event messages via the Serial Wire Output (SWO). This behaviour can be used by the Serial Wire Viewer (SWV) to output system events via a single pin:

Instrumentation trace ITM (printf-like Debugging)
Watchpoint Trace DWT, Instruction Pointer Trace
Event Trace (Interrupts)

The additional options of SWD (Serial Wire Debug) and SWO (Serial Wire Output) are fully supported by the UDE® Universal Debug Engine (UDE® Debugger) as well as by PLS' Universal Access Device 2pro (UAD2pro) family, UAD2next and UAD3+.

SWD Target Interface

High-speed downloading via SWD is achieved by the communication devices UAD2pro, UAD2next, and UAD3+ the hardware add-ons of the Universal Debug Engine.

SWD communication frequency @ 50 MHz.
2-wire SWD mode supported, SWO input supported.
I/O Voltage range: 1,65 Volts – 5,5 Volts, No power dissipation from target
ESD Protection per signal: 15kV, Capacity per signal: max 55pF
Resettable over-current protection for VIO:10A ( max 0.2s time to trip)
Optional with electrical isolation (1000 V RMS) available
Designed to use the recommended connector on the board with keying shroud
SWD interface is provided by a 10-pin or 20-pin target connector (50 mil Samtec FTSH-105 Cortex, 50 mil Samtec FTSH-110 Cortex, 100mil double row terminal).
LED for power indicating.

SWDIO, SWCLK and SWO are data and clock signals between the target system and the UAD2pro / UAD2next / UAD3+. These pins are used for communication with the target system and operate according to the meaning of the used SWD mode. The RESET# signal is driven from the UAD2/UAD3 to reset the target MCU.

Optional electrical isolation

The SWD adapter for UAD2pro, UAD2next, and UAD3+ is also available with electrical isolation of the SWD and JTAG interface. The communication frequency will be nevertheless 50 MHz.