Datasheet

402
2490R–AVR–02/2013
ATmega64(L)
4. Stabilizing time needed when changing OSCCAL Register
After increasing the source clock frequency more than 2% with settings in the OSCCAL reg-
ister, 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 ATmega64 is the only device in the scan chain, the problem is not visible.
– Select the Device ID Register of the ATmega64 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 ATmega64 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 ATmega64 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 reg-
ister triggers an unexpected EEPROM interrupt request.
Problem Fix / Workaround
Always use OUT or SBI to set EERE in EECR.