41.4.7 Threshold Comparison

At the end of each computation:

  • The conversion results are captured at the end-of-conversion.
  • The error (ADERR) is calculated based on a difference calculation which is selected by the CALC bits. The value can be one of the following calculations:
    • The first derivative of single measurements
    • The CVD result when double sampling is enabled
    • The current result vs. setpoint value in the ADSTPT register
    • The current result vs. the filtered/average result
    • The first derivative of the filtered/average value
    • Filtered/average value vs. setpoint value in the ADSTPT register
  • The result of the calculation (ADERR) is compared to the upper and lower thresholds, ADUTH and ADLTH registers, to set the UTHR and LTHR Status bits. The threshold logic is selected by the TMD bits. The threshold trigger option can be one of the following:
    • Never interrupt
    • Error is less than lower threshold
    • Error is greater than or equal to lower threshold
    • Error is between thresholds (inclusive)
    • Error is outside of thresholds
    • Error is less than or equal to upper threshold
    • Error is greater than upper threshold
    • Always interrupt regardless of threshold test results
    • If the Threshold condition is met, the channel threshold interrupt flag ADCHxIF is set.
Important:
  • The threshold tests are signed operations.
  • If the AOV bit is set, a threshold interrupt is signaled. It is good practice for threshold interrupt handlers to verify the validity of the threshold by checking the AOV bit.