43.6.13 Sleep Mode Operation
The Run in Standby bits in the Comparator n Control registers (COMPCTRLn.RUNSTDBY) control the behavior of the AC during standby sleep mode. Each RUNSTDBY bit controls one comparator. When the bit is zero, the comparator is disabled during sleep, but maintains its current configuration. When the bit is one, the comparator continues to operate during sleep. Note that when RUNSTDBY is zero, the analog blocks are powered off for the lowest power consumption. This necessitates a start-up time delay when the system returns from sleep.
For Window Mode operation, both comparators in a pair must have the same RUNSTDBY configuration.
When RUNSTDBY is one, any enabled AC interrupt source can wake up the CPU. The AC can also be used during sleep modes where the clock used by the AC is disabled, provided that the AC is still powered (not in shutdown). In this case, the behavior is slightly different and depends on the measurement mode, as listed in the following table.
| COMPCTRLn.MODE | RUNSTDBY=0 | RUNSTDBY=1 |
|---|---|---|
| 0 (Continuous) | GCLK_AC stopped, COMPx disabled | GCLK_AC stopped or running (depends on filtering options), COMPx enabled |
| 1 (Single-shot) | GCLK_AC stopped, COMPx disabled | GCLK_AC stopped, COMPx enabled only when triggered by an input event |
The Run in Standby bits in the Comparator n Control registers (COMPCTRLn.RUNSTDBY) also controls the behavior of the internal DAC during standby sleep mode, if the DAC is selected a positive or negative multiplexor input (COMPCTRLn.MUXPOS = INTDAC, COMPCTRLn.MUXNEG = INTDAC). When the bit is zero, the DAC is disabled during sleep, but maintains its current configuration. When the bit is one, the DAC continues to operate during sleep. Note that when RUNSTDBY is zero, the DAC blocks are powered off for the lowest power consumption. This necessitates a start-up time delay when the system returns from sleep.