Q: JTAG chain detection does not work with Atmel AVR
Answer:On some ATmega devices (i.e. Mega128L) IDCODE masks the data from TDI input The JTAG instruction IDCODE is not working correctly. Data to succeeding devices are replaced by all-ones during Update-DR.
If the Device IDs of all devices in the boundary scan chain are to be captured
simultaneously, the ATmega128 must be the fist device in the chain.
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