Datasheet

101
[Not recommended for new designs - Use XMEGA A1U series] XMEGA A1 [DATASHEET]
8067O–AVR–06/2013
18. DAC has up to ±10 LSB noise in Sampled Mode
If the DAC is running in Sample and Hold (S/H) mode and conversion for one channel is done at maximum rate
(i.e. the DAC is always busy doing conversion for this channel), this will block refresh signals to the second chan-
nel.
Problem fix/Workaround
When using the DAC in S/H mode, ensure that none of the channels is running at maximum conversion rate, or
ensure that the conversion rate of both channels is high enough to not require refresh.
19. Conversion lost on DAC channel B in event triggered mode
If during dual channel operation channel 1 is set in auto trigged conversion mode, channel 1 conversions are occa-
sionally lost. This means that not all data-values written to the Channel 1 data register are converted.
Problem fix/Workaround
Keep the DAC conversion interval in the range 000-001 (1 and 3 CLK), and limit the Peripheral clock frequency so
the conversion internal never is shorter than 1.5 µs.
20. Both DFLLs and both oscillators have to be enabled for one to work
In order to use the automatic runtime calibration for the 2 MHz or the 32 MHz internal oscillators, the DFLL for both
oscillators and both oscillators have to be enabled for one to work.
Problem fix/Workaround
Enable both DFLLs and both oscillators when using automatic runtime calibration for either of the internal
oscillators.
21. Access error when multiple bus masters are accessing SDRAM
If one bus master (CPU and DMA channels) is using the EBI to access an SDRAM in burst mode and another bus
master is accessing the same row number in a different BANK of the SDRAM in the cycle directly after the burst
access is complete, the access for the second bus master will fail.
Problem fix/Workaround
Do not put stack pointer in SDRAM and use DMA Controller in 1 byte burst mode if CPU and DMA Controller are
required to access SDRAM at the same time.
22. EEPROM page buffer always written when NVM DATA0 is written
If the EEPROM is memory mapped, writing to NVM DATA0 will corrupt data in the EEPROM page buffer.
Problem fix/Workaround
Before writing to NVM DATA0, for example when doing software CRC or flash page buffer write, check if EEPROM
page buffer active loading flag (EELOAD) is set. Do not write NVM DATA0 when EELOAD is set.
23. Pending full asynchronous pin change interrupts will not wake the device