Connecting to an aWire Target

The Atmel AVR ONE! can interface with the Atmel AVR UC3 L family of devices using the single-wire 'aWire' interface. The recommended pinout for the aWire interface is shown in Figure 1.

Be sure to use the correct orientation of the 6-pin header when connecting the AVR ONE! to the target application PCB. The stand-off adapters (provided) can be used to connect the AVR ONE! probe to both 100-mil and 50-mil target application connectors.

The aWire interface only requires one data line in addition to VCC and GND. The recommended 6-pin pinout is based on existing AVR interfaces, as well as the resources on the AVR ONE! debugger itself. When connecting to a target that does not have the standard 6-pin header, you can use the squid cable between the AVR ONE! 10-pin JTAG connector on the probe and the target board. Three connections are required, as described in the table below.

Table 1. Connecting to aWire using the Squid Cable
AVR ONE! JTAG probe Target pins Squid cable colors aWire pinout
Pin 1 (TCK)   Black  
Pin 2 (GND) GND White 6
Pin 3 (TDO) DATA Grey 1
Pin 4 (VTref) VTref Purple 2
Pin 5 (TMS)   Blue  
Pin 6 (nSRST)   Green  
Pin 7 (Not connected)   Yellow  
Pin 8 (nTRST)   Orange  
Pin 9 (TDI)   Red  
Pin 10 (GND)   Brown