The internal digital window comparator (DWC) is available in both conversion modes (manual and autonomous). The DWC outputs an internal ALERT signal. The internal ALERT signal can be output on any one of the digital output channels by configuring the ALERT_PIN register. Figure 7-5 provides a block diagram for the digital window comparator.

Figure 7-5 Digital Window Comparator Block Diagram

The low-side threshold, high-side threshold, event counter, and hysteresis parameters are independently programmable for each input channel. Figure 7-6 illustrates that the window comparator can monitor events for every analog input channel.

Figure 7-6 Event Monitoring With the Window Comparator

To enable the digital window comparator, set the DWC_EN bit in the GENERAL_CFG register. By default, hysteresis = 0, high threshold = 0xFFF, and low threshold = 0x000. For detecting when a signal is in-band, the EVENT_RGN register must be configured. In each of the cases shown in Figure 7-6, either or both ALERT_HIGH_FLAG and ALERT_LOW_FLAG can be set. The programmable event counter counts consecutive threshold violations before alert flags are set. The event count can be set to a higher value to avoid transients in the input signal setting the alert flags.

In order to assert the ALERT signal (internal) when the alert flag is set for a particular analog input channel, set the corresponding bit in the DWC_CH_SEL register. Alert flags are set, irrespective of the DWC_CH_SEL configuration, if DWC_EN = 1 and high or low thresholds are exceeded.