Figure 30-1. The Break Field
Frame
Header
Response
Response space
Break
field
Sync
field
Protected
identifier
field
Data 1
Data 2
Data N
Checksum
Inter-byte space
Inter-byte space
Break
delimiter
Break
Workaround
None
8. ADC measurement reports abnormal values with PSC2-synchronized conversions
When using ADC in synchronized mode, an unexpected extra Single ended conversion can spuriously re-start.
This can occur when the End of conversion and the Trigger event occur at the same time.
Workaround
No workaround
9. ADC amplifier measurement is unstable
When switching from a single-ended ADC channel to an amplified channel, noise can appear on the next ADC
conversion.
Workaround
After switching from a single ended to an amplified channel, discard the first ADC conversion.
10. PSC emulation
In emulation mode, TCNTn, OCRnx and ICRn 16-bit registers are accessed via the TEMP register. This can
induce an execution error, in step by step mode due to TEMP register corruption.
Workaround
No workaround
11. PSC OCRxx Register Update according to PLOCK2 Usage
If the PSC is clocked from PLL, and if PLOCK2 bit is changed at the same time as PSC end of cycle occurs, and if
OCRxx registers contents have been changed, then the updated OCRxx registers contents are not predictable.
The cause is a synchronization issue between two registers in two different clock domains (PLL clock which
clocks PSC and CPU clock).
Workaround
Enable the PSC end of cycle interrupt.
At the beginning of PSC EOC interrupt vector, change PLOCK value (OCRxx registers can be updated outside the
interrupt vector).
This process guarantees that UPDATE and PLOCK actions will not occur at the same moment.
12. Read / Write instructions of MUXn and REFS1:0 bits in the ADMUX Register during Analog conversion
during Analog conversion, the set or clear instructions of ADMUX channel and reference selection bits will fail.The
bits of the temporary buffer will be written in place of the final bits.
Workaround
Wait for the end of ADC conversion before any write of new channel or reference selection values in ADMUX.
308
ATmega16/32/64/M1/C1 [DATASHEET]
7647O–AVR–01/15
MICROCHIP [ MICROCHIP ]
