28.6.8 Oversampling and Decimation
By using oversampling and decimation, the ADC resolution can be increased from 12 bits up to 16 bits, for the cost of reduced effective sampling rate.
To increase the resolution by n bits, 4n samples must be accumulated. The result must then be right-shifted by n bits. This right-shift is a combination of the automatic right-shift and the value written to AVGCTRL.ADJRES. To obtain the correct resolution, the ADJRES must be configured as described in the table below. This method will result in n bit extra LSB resolution.
| Result Resolution | Number of Samples to Average | AVGCTRL.SAMPLENUM[3:0] | Number of Automatic Right Shifts | AVGCTRL.ADJRES[2:0] |
|---|---|---|---|---|
| 13 bits | 41 = 4 | 0x2 | 0 | 0x1 |
| 14 bits | 42 = 16 | 0x4 | 0 | 0x2 |
| 15 bits | 43 = 64 | 0x6 | 2 | 0x1 |
| 16 bits | 44 = 256 | 0x8 | 4 | 0x0 |