19.7.1 Control A

Table 19-4. Register Bit Attribute Legend
Symbol Description Symbol Description Symbol Description
R Readable bit HC Cleared by Hardware (Grey cell) Unimplemented
W Writable bit HS Set by Hardware X Bit is unknown at Reset
K Write to clear S Software settable bit
Name: CTRLA
Offset: 0x00
Reset: 0x00
Property: PAC Write-Protection, Write-Synchronized

Bit 76543210 
        SWRST 
Access R/W 
Reset 0 

Bit 0 – SWRST Software Reset

Writing a zero to this bit has no effect.

Setting this bit to 1 will reset all registers in the GCLK to their initial state after any reset, except for generic clocks and associated Generators that have their WRTLOCK bit in PCHCTRLm set to 1.

Refer to GENCTRL Reset Value for details on GENCTRL register reset.

Refer to PCHCTRL Reset Value for details on PCHCTRL register reset.

Due to synchronization, there is a waiting period between setting CTRLA.SWRST and a completed Reset. CTRLA.SWRST and SYNCBUSY.SWRST will both be cleared when the reset is complete.

ValueDescription
0 There is no Reset operation ongoing.
1 A Reset operation is ongoing.