Freescale Semiconductor M68HC08 manual Software Implementation, Initialization Setup

Software Implementation

5.3 Software Implementation

The general software implementation is illustrated in Figure 5-3. It incorporates the main routine entered from Reset and three interrupt states. The main routine includes the initialization of the microcontroller including PWM, HRP, ADC, and pins used in the application, and sets initial values for the PI regulator. The infinite loop is performed as long as board remains connected to the mains and no fault conditions are detected.

The interrupt states provide for trimming the internal oscillator, mains synchronization, reference sine wave generation, and fault detection and processing.

OverFlow Interrupt

of Timer, Fault

Interrupt

	Fault
	Interrupt	RESET
	Routine
done
PWM Reload Interrupt		MCU & Application
		Initialization
	Sinewave	done
	Generation
	Interrupt
done	Routine
		Main
		Infinite
		Loop
IRQ Interrupt

Synchronization

Interrupt

Routine

done

Figure 5-3. Software Implementation

5.3.1 Initialization Setup

Prior to running the main program loop, the initialization setup sets the microcontroller operation mode and peripherals. The quickest way to set and PWM is to use the auxiliary Excel sheet Reference [4]. To achieve the required system behavior and communication with peripherals, the following registers and initial values are set.

•Set configuration registers CONFIG1 and CONFIG2 at the beginning of the initialization; they can be written once only after each reset.

The register CONFIG1 sets:

–long COP time-out period

–enable LVI module

–disable STOP instruction

Dimmable Light Ballast with Power Factor Correction, Rev. 1

Freescale Semiconductor 39