User's Manual

Atmel AVR2042

8334A-AVR-05/11

6 Programming

On the ATxmega256A3, both programming and debugging can be done through two

physical interfaces.

The primary interface is the program and debug interface (PDI). This is a two-pin

interface using the reset pin for the clock input (PDI_CLK) and the dedicated test pin

for data input and output (PDI_DATA).

Programming and debugging can also be done through the four-pin JTAG interface.

The JTAG interface is IEEE 1149.1 standard compliant and supports boundary scan.

Any external programmer or on-chip debugger/emulator can be directly connected to

these interfaces, and no external components are required.

The Atmel REB-CBB provides a 10-pin header to connect the Atmel JTAGICE mkII

probe. This connection can be used for both protocols, JTAG and PDI.

Figure 6-1. Connection between JTAGICE mkII and REB-CBB.

To select between one of the protocols, the jumper DBGSEL has to be set to the

appropriate position. It routes test data input (signal TDI) to either TDI of the JTAG

interface or PDI of the Atmel proprietary PDI interface.

Figure 6-2. Debug interface.

NOTE Atmel JTAGICE mkII units with hardware revision 0 do not have PDI capabilities.

DBGSEL

RST

PDI

TDI

TMS

TDO

TCK

DBGSEL

DBG

PDI

JTAG