35.6.3 DMA Operation

The DAC generates the following DMA request:

• Data Buffer Empty (EMPTY): The request is set when data is transferred from DATABUF to the internal data buffer of DAC. The request is cleared when DATABUF register is written, or by writing a one to the EMPTY bit in the Interrupt Flag register (INTFLAG.EMPTY).

For each Start Conversion event, DATABUF is transferred into DATA and the conversion starts. When DATABUF is empty, the DAC generates the DMA request for new data. As DATABUF is initially empty, a DMA request is generated whenever the DAC is enabled.

If the CPU accesses the registers that are the source of a DMA request set/clear condition, the DMA request can be lost or the DMA transfer can be corrupted, if enabled.

When DAC registers are write-protected by Peripheral Access Controller, DATABUF cannot be written. To bypass DATABUF write protection, Bypass DATABUF Write Protection bit (CTRLB.BDWP) must be written to '1'