Troubleshooting Guide

Table 1. Troubleshooting Guide
Target type/family Problem Possible causes Solution
N/A Power LED does not light up DC supply voltage is insufficient or of incorrect polarity Check that you are using the correct power supply provided with the kit. If you are using another power supply, ensure that it has a center-positive connector.
Atmel megaAVR and Atmel AVR XMEGA JTAG debugging starts, then suddenly fails The JTAG Disable bit in the MCUCSR register has been inadvertently written by the application Hold reset low to regain control and change the code so that the JTAG Disable bit is not written
Atmel megaAVR and Atmel AVR XMEGA After using the Atmel AVR ONE! to download code to the device, the emulator no longer works

1. The JTAG ENABLE fuse has been disabled.

2. The programming interface is still active. It is not possible to use both OCD and programming at the same time.

1. Program the JTAG ENABLE fuse.

2. Close the Programming interface, then enter emulation mode.

Atmel megaAVR, Atmel AVR XMEGA, and Atmel tinyAVR Atmel AVR ONE! is detected by Atmel Studio or other software front-end, but it will not connect to target device

JTAG: JTAG ENABLE Fuse is not programmed

debugWIRE: DWEN Fuse is not programmed

JTAG: Use an other programming interface to program the JTAG ENABLE Fuse

debugWIRE: Use an other programming interface to program the DWEN Fuse

Atmel megaAVR, Atmel AVR XMEGA, and Atmel AVR UC3 JTAG Debugging and programming is unstable, or does not work at all For some target board configurations there might be some ringing on the interface lines Add series resistors on the JTAG lines, especially TCK, but series resistors could be useful on TMS and TDI too. A value of about 68Ω will in most cases be suitable. Note that you might have to reduce the JTAG clock frequency after adding the series resistors.
N/A Atmel Studio gives a message that no voltage is present

1. No power on target board.

2. Vtref not connected.

3. Target voltage too low.

1. Apply power to target board.

2. Make sure your JTAG connector includes the Vtref signal.

3. Make sure the target power supply is able to provide enough power.

Atmel megaAVR OCD fuse is disabled, but using the Atmel AVR ONE!, OCD is still possible The AVR ONE! will automatically program the OCD fuse if it is disabled This is correct operation
Atmel megaAVR and Atmel tinyAVR Some I/O registers are not updated correctly in Atmel Studio I/O view When non-intrusive read back is not possible, the Atmel AVR ONE! will not update this location in the Atmel Studio I/O view Read this I/O location into a temporary register, and view it there during debugging. See the chapter "Special Considerations" for information about which registers affected by this.
Atmel tinyAVR and Atmel megaAVR with debugWIRE support SPI programming after a debugWIRE session is not possible When the debugWIRE Interface is enabled the SPI Interface is disabled Re-enable the SPI Interface as described in the section "Connecting to Target through the debugWIRE Interface". Use command line software to re-enable SPI interface.
Atmel tinyAVR and Atmel megaAVR with debugWIRE support Neither SPI nor debugWIRE connection works The SPI and debugWIRE interfaces are disabled. DebugWIRE will not work if the lockbits are programmed. Connect to target with High Voltage Programming. Enable SPI or debugWIRE and clear lockbits if using debugWIRE.
Atmel megaAVR, Atmel tinyAVR, Atmel AVR XMEGA, and Atmel AVR UC3 Error messages, or other strange behavior when using debugWIRE or JTAG Target is running outside Safe Operation Area. Maximum frequency vs. VCC. Make sure the target is running within the Safe Operation Area as described in the chapter "Electrical Characteristics" in the datasheet for the actual part. Lower the frequency and/or increase the voltage.