18.4.2.3.1 Input Sample Validity Checking

The CIC filter checks whether input samples fall within a valid range, which can be configured by the user using the THIGH (CICINTHR[31:16]) and TLOW (CICINTHR[15:0]) thresholds. If the current input sample is below the threshold defined by TLOW, the module will increase the LIISCNT (CICIISxSTAT[11:0]) count. If the input sample is above the threshold defined by THIGH, the module will increase the HIISCNT (CICIISxSTAT[27:16]) count. Regardless of whether the input sample is valid or invalid, it will still be processed by the subsequent stages of the CIC filter.

TLOW and THIGH are the values stored in the CICINTHR register. The counted value of invalid samples will be updated in the CICIISxSTAT register (HIISCNT and LIISCNT bits) when a CIC output sample is generated. If an invalid input is detected on any channel, the IISERR (CICSTAT[20]) bit will be set, and an interrupt will be asserted.