SWD Pinout

The SAM-ICE JTAG connector is also compatible to ARM’s Serial Wire Debug (SWD).

Figure 1. SWD Pinout

The table below lists the SAM-ICE SWD pinout.

Table 1. SWD Pinout
Pin Signal Type Description
1 VTref Input

This is the target reference voltage.

It is used to check if the target has power, to create the logic-level reference for the input comparators and controls the output logic levels to the target. It is normally fed from VDD on the target board and must not have a series resistor.

2   NC

This pin is not connected

3   NC

This pin is not used. If the device may also be accessed via JTAG, this pin may be connected to nTRST, otherwise leave open.

4 GND   Common ground
5   NC

This pin is not used. If the device may also be accessed via JTAG, this pin may be connected to TDI, otherwise leave open.

6 GND  

Common ground

7 SWDIO Input/Output

Single bi-directional data pin. A pull-up resistor is required. ARM recommends 100kΩ.

8 GND  

Common ground

9 SWCLK Output

Clock signal to target CPU. It is recommended that this pin is pulled to a defined state on the target board. Typically connected to TCK of target CPU.

10 GND  

Common ground

11   NC

This pin is not used by the SAM-ICE when operating in SWD mode. If the device may also be accessed via JTAG, this pin may be connected to RTCK, otherwise leave open.

12 GND  

Common ground

13 SWO Input

Serial Wire Output trace port. (Optional, not required for SWD communication.)

14 GND  

Common ground

15 RESET Input/Output

Target CPU reset signal. Typically connected to the RESET pin of the target CPU, which is typically called "nRST", "nRESET", or "RESET".

16 GND  

Common ground

17   NC

This pin is not connected in SAM-ICE

18 GND  

Common ground

19   NC

This pin is not connected in SAM-ICE

20 GND  

Common ground