Connecting to an SWD Target

The ARM SWD interface is a subset of the JTAG interface, making use of the TCK and TMS pins, which means that when connecting to an SWD device, the 10-pin JTAG connector can technically be used. The ARM JTAG and AVR JTAG connectors are, however, not pin-compatible, so this depends upon the layout of the target board in use. When using an STK600 or a board making use of the AVR JTAG pinout, the AVR connector port on the Power Debugger must be used. When connecting to a board, which makes use of the ARM JTAG pinout, the SAM connector port on the Power Debugger must be used.

The recommended pinout for the 10-pin Cortex Debug connector is shown in Figure 1.

Connection to a 10-pin 50-mil Cortex Header

Use the flat cable (included in some kits) to connect to a standard 50-mil Cortex header.

Connection to a 10-pin 100-mil Cortex-layout Header

Use the adapter board (included in some kits) to connect to a 100-mil Cortex-pinout header.

Connection to a 20-pin 100-mil SAM Header

Use the adapter board (included in some kits) to connect to a 20-pin 100-mil SAM header.

Connection to a Custom 100-mil Header

The 10-pin mini-squid cable should be used to connect between the Power Debugger AVR or SAM connector port and the target board. Six connections are required, as described in the table below.

Table 1. Power Debugger SWD Pin Mapping
Name AVR PORT Pin SAM PORT Pin Description
SWDCLK 1 4 Serial Wire Debug Clock.
SWDIO 5 2 Serial Wire Debug Data Input/Output.
SWO 3 6 Serial Wire Output (optional- not implemented on all devices).
nSRST 6 10 Reset.
VTG 4 1 Target voltage reference.
GND 2, 10 3, 5, 9 Ground.