30.5.1 Control A
If an NMI has been triggered this register is not writable.
| Name: | CTRLA |
| Offset: | 0x00 |
| Reset: | 0x00 |
| Property: | - |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| RESET | NMIEN | ENABLE | |||||||
| Access | R/W | R/W | R/W | ||||||
| Reset | 0 | 0 | 0 |
Bit 7 – RESET Reset CRCSCAN
Writing this bit to ‘1’ resets the CRCSCAN. The
CRCSCAN Control and Status (CRCSCAN.CTRLA, CRCSCAN.CTRLB, CRCSCAN.STATUS)
register will be cleared one clock cycle after the RESET bit is written to
‘1’.
If NMIEN is ‘0’, this bit is writable both when the
CRCSCAN is busy (the BUSY bit in CRCSCAN.STATUS is ‘1’) and not
busy (the BUSY bit is ‘0’), and will take effect immediately.
If NMIEN is ‘1’, this bit is only writable when the
CRCSCAN is not busy (the BUSY bit in CRCSCAN.STATUS is ‘0’).
The RESET bit is a strobe bit.
Bit 1 – NMIEN Enable NMI Trigger
When this bit is written to ‘1’, any CRC failure
will trigger an NMI.
This bit can only be cleared by a System Reset. It is not cleared by a write to the RESET bit.
This bit can only be written to ‘1’ when the
CRCSCAN is not busy (the BUSY bit in CRCSCAN.STATUS is
‘0’).
Bit 0 – ENABLE Enable CRCSCAN
Writing this bit to ‘1’ enables the CRCSCAN with the current
settings. It will stay ‘1’ even after a CRC check has
completed, but writing it to ‘1’ again will start a new check.
Writing the bit to ‘0’ has no effect.
The CRCSCAN can be configured to run a scan during the
microcontroller (MCU) start-up sequence to verify the Flash sections before
letting the CPU start normal code execution (see the 30.3.1 Initialization section). If this feature is enabled, the ENABLE bit will
read as ‘1’ when normal code execution starts.