Datasheet

47.6.9.5 Dithering Mode
Dithering is enabled by setting DACCTRLx.DITHER to 1. In dithering mode, DATAx is a 16-bit unsigned
value where DATAx[15:4] is the 12-bit data converted by DAC and DATAx[3:0] represent the dither bits,
used to minimize the quantization error.
The principle is to make 16 sub-conversions of the DATAx[15:4] value or the (DATAx[15:4] + 1) value, so
that by averaging those two values, the conversion result of the 16-bit value (DATAx[15:0]) is accurate.
To operate, the STARTx event must be configured to generate 16 events for each DATAx[15:0]
conversion, and DATABUFx must be loaded every 16 DAC conversions. EMPTYx event and DMA
request are therefore generated every 16 DATABUFx to DATAx transfer. STATUS.EOCx still reports end
of each sub-conversions.
Following timing diagram shows examples with DATA0[15:0] = 0x1204 followed by DATA0[15:0] =
0x1238.
Figure 47-5. DAC Conversions in Dithering Mode
0x1204
0x1200
0x1210
DATA0[15:0]
0x1230
0x1240
0x1238
1
2 3 4 5 6
7
8 9 10 11 12 13 14 15 16
1
2 3 4 5 6
7
8 9 10 11 12 13 14 15 16
VOUT0
sub-conversion
47.6.9.6 Interpolation Mode
The DAC provides interpolation that allows for oversampling ratios (OSR) of 2x, 4x, 8x, 16x or 32x.
Interpolation mode is selected by writing a non-zero value to the Oversampling Ratio bits in the DACx
Control register (DACCTRLx.OSR).
The data is sampled once over OSR trigger events and then recomputed at the trigger sample rate using
a third-order SINC filter.
The figures below show the spectral mask of the SINC filter depending on the selected OSR. 

is the
sampling frequency of the input signal which corresponds to the trigger frequency divided by OSR.
The Filter usage bit DACCTRLx.FEXT determines whether the filter is integrated to the corresponding
DAC or used as a standalone filter driven by DMA. If DACCTRLx.FEXT=0, the DAC takes the filter output
while the value of RESULTx is reading zero. Conversely, If DACCTRLx.FEXT=1, the DAC value remains
zero, and the value of RESULTx register reflects the filter output.
SAM D5x/E5x Family Data Sheet
DAC – Digital-to-Analog Converter
© 2019 Microchip Technology Inc.
Datasheet
DS60001507E-page 1681