2.2.1 SWD Pinout

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

The table below lists the SAM-ICE SWD pinout.

Table 2-2. 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 V_DD 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