The RT1170 supports the ability to trigger dual ADC’s in SyncMode or AsyncMode via the ADC External Trigger Control (ADC_ETC):
- In SyncMode, ADC1 and ADC2 are controlled by the same trigger source.
- In AsyncMode, ADC1 and ADC2 are controlled by separate trigger source.
In AsyncMode (TRIGa_CTRL[SYNC_MODE]==0), the ADC conversion clock frequency maximum is 88 MHz, but in SyncMode (TRIGa_CTRL[SYNC_MODE]==1), the ADC conversion clock frequency must be constraint to a lower frequency due to switching noise inherent to its design architecture. Reducing the conversion clock frequency reduces the switching noise that is observed.
NXP is currently conducting further characterization in order to specify the maximum frequency of conversion in SyncMode across process, voltage, and temperature. However, on typical samples at room temperature 60 MHz is the maximum frequency.
