14 Getting Started with Software Development

By design, this device has functional safety features that cannot be disabled. The Error Controller (ERRCTRL), in particular, can generate interrupts, float I/O pins, and even reset the device. Refer to the ERRCTRL - Error Controller section for additional information. Although these features may be required in a completed system, they can make initial software development difficult because there is not yet any code to properly handle these situations. For getting started with software development, it is thus recommended to immediately configure the ERRCTRL as follows at device start-up:

1. Read the ERRCTRL.ESF (Error Status Flags) register; if it is not zero, write ‘0xFFFFFFFF’ to the register to clear it
2. Place the ERRCTRL in the configuration state by performing a protected write of CONFIG to the STATE bit field of the CTRLA (Control A) register
3. Select an error severity level of NOTIFICATION for each ESCn (Error Source Control n) register by writing NOTIFICATION to the ERRLVL bit field; this ensures that the ERRCTRL will neither generate interrupts nor reset the system
4. Place the ERRCTRL back in the normal state by performing a protected write of NORMAL to the STATE bit field of the CTRLA register

Example code for performing these steps is as follows:

	if (ERRCTRL.ESF)
	{
		ERRCTRL.ESF = 0xFFFFFFFF; // Clear all Error Status Flags
	}
	_PROTECTED_WRITE(ERRCTRL.CTRLA, ERRCTRL_STATE_CONFIG_gc); // Place ERRCTRL in CONFIG state
	ERRCTRL.ESCVREGFAIL = ERRCTRL_ERRLVL_NOTIFICATION_gc; // Select severity level of
	ERRCTRL.ESCBUSERR = ERRCTRL_ERRLVL_NOTIFICATION_gc; // NOTIFICATION for all error channels
	ERRCTRL.ESCRAM2 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCFLASH2 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCOPC = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCSPLIM = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCRAM1 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCFLASH1 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCVREGWARN = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCCFD0 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCCFD1 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCCFM0 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCCFM1 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCSWDT = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCEEPROM = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCEVSYS0 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	ERRCTRL.ESCEVSYS1 = ERRCTRL_ERRLVL_NOTIFICATION_gc;
	_PROTECTED_WRITE(ERRCTRL.CTRLA, ERRCTRL_STATE_NORMAL_gc); // Place ERRCTRL in NORMAL state