pwm_demo1/main.c

===== Description =====

This demo shows how to configure a Relocatable Port as a PWM channel. The SBC66 Netcruzer boards have 9 PWM channels. They can be assigned to any of the Relocatable Ports. For the location of the Relocatable Ports, see modtronix.com/product/sbc66ec/ For this demo, connect a LED to port 6 (old port name X6), with anode to port 6 and cathode to 0V via a 1k resistor. Or, the DB66DEV1 development board can be used, which has LED1 on this port. This demo configures port 6 (old port name X6) as a PWM output, and will gradually increase and decrease the brightness of the LED every second.

• At startup duty cycle of PWM output is 0
• During next second will gradually increase duty cycle every 10 milli seconds by 1%, until it reaches 100% (fully on)
• During next second will gradually decrease duty cycle every 10 milli seconds by 1%, until it reaches 0% (fully off)
• Repeats steps 2 and 3. Additionally it will blink the System LED every second.

===== Required Hardware =====

This project can be run on any of our SBC66 Netcruzer boards. For prototyping, we recommend combining this board with a Prototyping Board, like the PT66ECI for example. This low cost prototyping board makes all the I/O ports of the SBC66 board available via marked labels on the PCB. It also provides a reset and firmware button that simplifies prototyping.

===== Building Project =====

This project is located in the "src/demos/pwm/pwm_demo1" folder of the Netcruzer Download. To compile for Netcruzer Board, open this project in MPLAB X, and select the "Project Configuration" for desired board. For example "SBC66ECL_R2" for the SBC66ECL Revision 2 board. For details click here

===== Programming Board =====

After compiling (build), the board can be programmed via the USB Bootloader or a PIC Programmer. USB Programming is simplified when using the SBC board together with a Prototype Board.

===== File History =====

2012-08-08, David H. (DH):

• Initial version

#define THIS_IS_MAIN_FILE   //Uniquely identifies this as the file with the main application entry function main()

#include "HardwareProfile.h"            //Required for all Netcruzer projects

int main(void)
{
    BYTE pwmValue = 0;          //Pwm value from 0 to 100 (0 to 100%)
    BOOL pwmDecInc = TRUE;      //Flag used to indicate if PWM duty cycle is currently decreasing (0), or increasing (1)

    //Declare all timers, and initialize with current timer value (tick16Get...() functions)
    WORD tmrFlashLed = tick16Get();     //Timer for flashing system LED
    WORD tmrAdjustPWM = tick16Get();    //Timer for flashing system LED

    nzSysInitDefault();         //Default initialization. All ports inputs. All analog features disabled. Tick 1ms

    DIR_SYSLED = 0; //Set System LED port as outputs. Setting DIR_xxx to 1 set's port to input, and 0 as output

    //Configure Port 6 (old port name X6) (LED1 on DB66DEV1) as PWM channel 2, with default frequency of 16kHz.
    //The value of the PWM2_FREQ define determines the frequency, and is 16kHz by default.
    //To change the default frequency, do one of the following:
    // - Redefine PWM2_FREQ in projdefs.h file for desired frequency (For example: #define PWM2_FREQ  PWM_FREQ_80KHZt)
    // - Call pwm2SetPeriod() with period for desired frequency
    pwm2OpenDefault(PPS_OUT_06, 0);

    while(1)
    {
        //Adjust PWM value every 10ms
        if (tick16TestTmr(tmrAdjustPWM)) {
            tick16UpdateTmrMS(tmrAdjustPWM, 10);  //Update timer to expire in 10ms again

            if (pwmDecInc == TRUE)
                pwmValue++;
            else
                pwmValue--;

            pwm2SetPercent(PWM2_FREQ, pwmValue);   //Set duty cycle (in percentage) of PWM channel 2

            if ( ((pwmDecInc==FALSE)&&(pwmValue==0)) || ((pwmDecInc==TRUE)&&(pwmValue==100)) ) {
                pwmDecInc = !pwmDecInc;
            }
        }

        //Flash system LED every 500ms
        if (tick16TestTmr(tmrFlashLed)) {
            tick16UpdateTmrMS(tmrFlashLed, 500); //Update timer to expire in 500ms again
            LAT_SYSLED = !LAT_SYSLED;       //Toggle System LED
        }
    }//end while

    return 0;
}//end main