15.5.1 Control A
| Name: | CTRLA | 
| Offset: | 0x00 | 
| Reset: | 0x00 | 
| Property: | Configuration Change Protection | 
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| IVSEL | CVT | LVL0RR | |||||||
| Access | R/W | R/W | R/W | ||||||
| Reset | 0 | 0 | 0 | 
Bit 6 – IVSEL Interrupt Vector Select
When the entire Flash is configured as a BOOT section, this bit will be ignored.
Note: 
                    
            - A system reset will cause the Program Counter to be reset to 0x0000, regardless of the IVSEL bit value.
 
| Value | Description | 
|---|---|
| 0 | The expected location of the interrupt vectors is directly after the BOOT section(1) | 
| 1 | The expected location of the interrupt vectors is at the start of the BOOT section | 
Bit 5 – CVT Compact Vector Table
| Value | Description | 
|---|---|
| 0 | Compact Vector Table function is disabled | 
| 1 | Compact Vector Table function is enabled | 
Bit 0 – LVL0RR Round Robin Priority Enable
| Value | Description | 
|---|---|
| 0 | Priority is fixed for priority level 0 interrupt requests: The lowest interrupt vector address has the highest priority. | 
| 1 | The round robin priority scheme is enabled for priority level 0 interrupt requests | 
