4. Stabilizing time needed when changing OSCCAL Register
After increasing the source clock frequency more than 2% with settings in the OSCCAL register, the device
may execute some of the subsequent instructions incorrectly.
Problem Fix / Workaround
The behavior follows errata number 3., and the same Fix / Workaround is applicable on this errata.
5. IDCODE masks data from TDI input
The JTAG instruction IDCODE is not working correctly. Data to succeeding devices are replaced by all-ones
during Update-DR.
Problem Fix / Workaround
–
–
If ATmega64A is the only device in the scan chain, the problem is not visible.
Select the Device ID Register of the ATmega64A by issuing the IDCODE instruction or by entering the
Test-Logic-Reset state of the TAP controller to read out the contents of its Device ID Register and
possibly data from succeeding devices of the scan chain. Issue the BYPASS instruction to the
ATmega64A while reading the Device ID Registers of preceding devices of the boundary scan chain.
–
If the Device IDs of all devices in the boundary scan chain must be captured simultaneously, the
ATmega64A must be the first device in the chain.
6. Reading EEPROM by using ST or STS to set EERE bit triggers unexpected interrupt request.
Reading EEPROM by using the ST or STS command to set the EERE bit in the EECR register triggers an
unexpected EEPROM interrupt request.
Problem Fix / Workaround
Always use OUT or SBI to set EERE in EECR.
ATmega64A [DATASHEET]
12
8160DS–AVR–02/2013
ATMEL [ ATMEL ]
