Datasheet

17
ATmega16A [DATASHEET]
Atmel-8154CS-8-bit-AVR-ATmega16A_Datasheet Summary-07/2014
10. Errata
The revision letter in this section refers to the revision of the ATmega16A device.
10.1 ATmega16A rev. N to rev. Q
• First Analog Comparator conversion may be delayed
• Interrupts may be lost when writing the timer registers in the asynchronous timer
• IDCODE masks data from TDI input
• Reading EEPROM by using ST or STS to set EERE bit triggers unexpected interrupt request
1. First Analog Comparator conversion may be delayed
If the device is powered by a slow rising V
CC
, the first Analog Comparator conversion will take longer than
expected on some devices.
Problem Fix/Workaround
When the device has been powered or reset, disable then enable theAnalog Comparator before the first
conversion.
2. Interrupts may be lost when writing the timer registers in the asynchronous timer
The interrupt will be lost if a timer register that is synchronous timer clock is written when the asynchronous
Timer/Counter register (TCNTx) is 0x00.
Problem Fix/Workaround
Always check that the asynchronous Timer/Counter register neither have the value 0xFF nor 0x00 before
writing to the asynchronous Timer Control Register (TCCRx), asynchronous Timer Counter Register
(TCNTx), or asynchronous Output Compare Register (OCRx).
3. 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 ATmega16A is the only device in the scan chain, the problem is not visible.
– Select the Device ID Register of the ATmega16A 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
ATmega16A 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
ATmega16A must be the fist device in the chain.
4. 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.