1

Open the MPLAB X IDE and also the MPLAB Code Configurator under theTools > Embedded menu of MPLAB X IDE.

2

Click on theSystem Module and the MCC screen will show the Easy Setup menu. Select theINTOSC in the Oscillator Select box. Then selectFOSC in theSystem Clock Select window. Finally, select2 MHz_HF in the Internal Clock selection window. This will be the clock for the PIC16F1508. Settings are shown here:

3

Next, choose thePWM4 andTMR2 blocks underDevice Resources by double-clicking on them. This will add them to the project.

4

Setting upTimer2 will control the period of the PWM signal.
Click on theTMR2 resource to configure it for PWM. Check theEnable Timer box. UnderTimer Clock set thePrescaler to1:64. Enter20 ms in theTimer Period box. This will configure the PWM for close to a 20 millisecond period.

5

ThePWM peripheral is setup next.

• Click onPWM4 to open theEasy Setup window.
• Make sure theEnable PWM and theEnable Pin Output are both checked.
• In theSelect a Timer box chooseTimer 2.
• SetDuty Cycle to50%.
• The PWM Period will show a value close to 20 milliseconds.

6

Click on thePin Module8 resource.
Under thePin Manager graphic, click on the blue lock at the PORT C bit 1 column in the PWM4 row to change it to green.
In thePin Module Easy Setup window, uncheck theAnalog box leaving just theOutput box checked.

7

Click on theGenerate button in theProject Resources header to generate the project code.

8

Add setup code under the// initialize the device section of the generatedmain.c file.

// initialize the device    SYSTEM_Initialize();    uint16_t dutycycle;    //clear out any stored value    dutycycle = 0;

In themainwhile(1) loop add the following code after the**// Add your application code** comment line.

       for( dutycycle = 30; dutycycle < 65; dutycycle ++){  //cycle duty cycle from 30 to 65       PWM4_LoadDutyValue(dutycycle);       __delay_ms(20);    }       for( dutycycle <= 65; dutycycle > 30; dutycycle --){ //cycle duty cycle from 65 to 30       PWM4_LoadDutyValue(dutycycle);       __delay_ms(20);    }

The values fordutycycle are not a percentage of the waveform but rather the values that fill the10-bit register pair PWMxDCH and PWMxDCL in the PWM peripheral. Based on theTimer2 PR2 setting from step 4, a 100% duty cycle has the value of 624, so 30 is roughly 5% of that and 65 is roughly 10%. With a 20 millisecond period, this produces approximately a 1 ms (30) and 2 ms (65) pulse respectively.

9

Click on theMake and Program Device icon. This builds the project and launches the programmer.
In theOutput window you should see a series of messages and, if successful, it ends with a "Programming and Verify Successful" message and the servo connected to RC1 pin begins moving back and forth.

10

Success!
The servo moves back and forth from the pulses produced in the PWM peripheral.