47.6.9.3 Conversion Refresh

Conversion Refresh only works when the input data is not interpolated, i.e. the Oversampling Rate in the DAC Control register is zero (DACCTRLx.OSR=0x0).

The DAC can only maintain its output within one LSB of the desired value for approximately 100µs. When a DAC is used to generate a static voltage or at a rate less than 20kSPS, the conversion must be refreshed periodically. The OSCULP32K clock can start new conversions automatically after a specified period. Write a value to the Refresh bit field in the DAC Control x register (DACCTRLx.REFRESH[3:0]) to select the refresh period according to the formula:

T_{REFRESH} = REFRESH \times T_{OSCULP32K}

The actual period will depend on the tolerance of the OSCULP32K (see Electrical Characteristics).

If DACCTRLx.REFRESH=0, there is no conversion refresh. DACCTRLx.REFRESH=1 is Reserved.

If no new conversion is started before the refresh period is completed, DACx will convert the DATAx value again.

In standby sleep mode, the refresh mode remains enabled if DACCTRLx.RUNSTDBY=1.

If DATAx is written while a refresh conversion is ongoing, the conversion of the new content of DATAx is postponed until DACx is ready to start the next conversion.