When the ADC performs a calibration, the calibration constants are stored in an array which is accessible through the Calibration Values register (Addr: 5h). To save the time it takes to execute a calibration, t_CAL, or to allow re-use of a previous calibration result, these values can be read from and written to the register at a later time. For example, if an application requires the same input impedance, R_IN, this feature can be used to load a previously determined set of values. For the calibration values to be valid, the ADC must be operating under the same conditions, including temperature, at which the calibration values were originally determined by the ADC.

To read calibration values from the SPI, do the following:

1. Set ADC to desired operating conditions.
2. Set the SSC bit (Addr: 4h; Bit: 7) to 1.
3. Read exactly 240 times the Calibration Values register (Addr: 5h). The register values are R0, R1, R2... R239 where R0 is a dummy value. The contents of R<239:1> should be stored.
4. Set the SSC bit (Addr: 4h; Bit: 7) to 0.
5. Continue with normal operation.

To write calibration values to the SPI, do the following:

1. Set ADC to operating conditions at which Calibration Values were previously read.
2. Set the SSC bit (Addr: 4h; Bit: 7) to 1.
3. Write exactly 239 times the Calibration Values register (Addr: 5h). The registers should be written with stored register values R1, R2... R239.
4. Make two additional dummy writes of 0000h.
5. Set the SSC bit (Addr: 4h; Bit: 7) to 0.
6. Continue with normal operation.