4. Stabilizing time needed when changing OSCCAL Register
After increasing the source clock frequency more than 2% with settings in the OSC-
CAL register, the device may execute some of the subsequent instructions
incorrectly.
Problem Fix / Workaround
The behavior follows errata number 1., 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 fist device in the chain.
18
ATmega64(L)
2490LS–AVR–10/06
ATMEL [ ATMEL ]
