JAJSN92 December 2022 AFE78101 , AFE88101
PRODUCTION DATA
Channel 0 of the CCS pointer is named OFFSET. The OFFSET channel is used to calibrate and improve the ADC offset performance. Convert the OFFSET channel, and use the result as a calibration for the ADC offset in subsequent measurements.
This ADC channel samples VREF / 2 and compares this result against 7FFh as a measure of the ADC offset. The data rate for the ADC measuring this channel is 2560 Hz. The ADC conversion for the OFFSET channel is subtracted from 7FFh and the resulting value is stored in ADC_OFFSET (28h). The offset can be positive or negative; therefore, the value is stored in 2’s complement notation.
With the subtraction from 7FFh, ADC_OFFSET is the negative of the offset. This value is subtracted from conversions of the ADC by default. For direct measurements of the ADC, set ADC_BYP.OFST_BYP_EN to 1 to enable the offset bypass.