37.7.1 Control A

Name: CTRLA
Offset: 0x00
Reset: 0x00
Property: PAC Write-Protection, Write-Synchronized Bits

Bit 76543210 
 ONDEMANDRUNSTDBYSLAVEEN   ENABLESWRST 
Access R/WR/WR/WR/WR/W 
Reset 00000 

Bit 7 – ONDEMAND On Demand Control

The On Demand operation mode allows the ADC to be enabled or disabled, depending on other peripheral requests.

In On Demand operation mode, i.e., if the ONDEMAND bit has been previously set, the ADC will only be running when requested by a peripheral. If there is no peripheral requesting the ADC will be in a disabled state.

If On Demand is disabled the ADC will always be running when enabled.

In standby sleep mode, the On Demand operation is still active if the CTRLA.RUNSTDBY bit is '1'. If CTRLA.RUNSTDBY is '0', the ADC is disabled.

Note: This bit is not synchronized.

For the client ADC, this bit has no effect when the SLAVEEN bit is set (CTRLA.SLAVEEN= 1). ONDEMAND bit from host ADC instance will control the On Demand operation mode.

ValueDescription
0 The ADC is always on , if enabled.
1 The ADC is enabled, when a peripheral is requesting the ADC conversion. The ADC is disabled if no peripheral is requesting it.

Bit 6 – RUNSTDBY Run in Standby

This bit controls how the ADC behaves during standby sleep mode.

Note: This bit is not synchronized.

For the client ADC, this bit has no effect when the SLAVEEN bit is set (CTRLA.SLAVEEN= 1). RUNSTDBY bit from host ADC instance will control the client ADC operation in standby sleep mode.

ValueDescription
0 The ADC is halted during standby sleep mode.
1 The ADC is not stopped in standby sleep mode. If CTRLA.ONDEMAND=1, the ADC will be running when a peripheral is requesting it. If CTRLA.ONDEMAND=0, the ADC will always be running in standby sleep mode.

Bit 5 – SLAVEEN Client Enable

This bit enables the host/client operation and it is available only in the client ADC instance (ADC1).

Note: This bit is not synchronized.

This bit can be set only for the client ADC (ADC1). For the host ADC (ADC0), this bit is always read zero.

ValueDescription
0 The host-client operation is disabled.
1 The ADC1 is enabled as a client of ADC0

Bit 1 – ENABLE Enable

Note: This bit is write-synchronized: SYNCBUSY.ENABLE must be checked to ensure the CTRLA.ENABLE.

For the client ADC, this bit has no effect when the SLAVEEN bit is set (CTRLA.SLAVEEN= 1).

ValueDescription
0 The ADC is disabled.
1 The ADC is enabled.

Bit 0 – SWRST Software Reset

Writing a '0' to this bit has no effect.

Writing a '1' to this bit resets all registers in the ADC, except DBGCTRL, to their initial state, and the ADC will be disabled.

Writing a '1' to CTRL.SWRST will always take precedence, meaning that all other writes in the same write-operation will be discarded.

Note: This bit is write-synchronized: SYNCBUSY.SWRST must be checked to ensure the CTRLA.SWRST synchronization is complete.
ValueDescription
0 There is no reset operation ongoing.
1 The reset operation is ongoing.