Stap 3: De programma-Code
/*************************************************************************** * PWMdemo.c: * * Dependencies: wiringPi must be installed. * Instructions for download, install and use * are located at wiringpi.com * * Compile with: gcc -o PWMdemo PWMdemo.c -lwiringPi * * All pin numbers are wiringPi numbers unless otherwise specified. * * Pin 1 is the only hardware PWM pin available on all RaspberryPi models. * It is physical pin number 12 on the GPIO header. * * Pin 24 is the second hardware PWM pin available on model B+ only. * It is physical pin number 35 on the GPIO header. * * There is an LED (with series resistor) connected to PWMpin and ground. * An oscilloscope can be connected to PWMpin and ground. * * You can hear the tones if speakers are connected to the audio jack. * Changing the various settings can make the tones very loud. * * Menu choices: * * 1 Fade In-Out - Runs through a for loop one time. * It runs from 0 to 100% to 0 of the duty cycle in the * number of steps specified in the range. * * 2 Toggle the PWM mode between balanced and mark:space. * * 3 Set the range, the number of duty cycle steps between 0 and 100%. * * 4 Change the PWM clock. * * 5 Set the duty cycle. The duty cycle should not be greater than the range. * Duty cycle is 100% if duty cycle equals range. * * 6 QUIET sets duty cycle to zero. * ***************************************************************************/
#include <wiringPi.h> #include <stdio.h> #define clrscr() printf("\e[1;1H\e[2J") // Clear screen. int PWMpin= 1; // 1 right (Or 24 left if model B+). /*************************************************************************** * menu() function - Display the menu and execute the choices. ***************************************************************************/ void menu(void) { int range = 1024; // value passed to pwmSetRange. int clock = 32; // value passed to pwmSetClock. int mode = 0; // 0=balanced, 1=mark:space int duty = 0; // Duty cycle int choice=0; int i; // Index for fade for loop. int x; // Fade in/out switch. while(1) // Display the menu. { clrscr(); printf("\n\n Pulse Width Modulation Demonstration\n\n\n"); printf(" 1 - Fade In - Out\n"); printf(" 2 - Toggle PWM Mode: "); if(mode==0) printf("Balanced\n"); else printf("Mark:Space\n"); printf(" 3 - Set Range: %d\n", range); printf(" 4 - Set Clock: %d\n", clock); printf(" 5 - Set Duty Cycle: %d\n",duty); printf(" 6 - QUIET\n\n\n"); printf(" Press Selection: "); scanf("%d", &choice); switch(choice) // Execute the choice. { case 1: // Fade duty cycle within 0 - range - 0. clrscr(); x = 1; for (i=0; i>-1; i+=x) { pwmWrite(PWMpin, i); printf(" %d\n", i); delay (7); if(i > range) x = -1; } pwmWrite(PWMpin, 0); duty=0; break; case 2: // toggle PWM mode Mark:Space/Balanced. mode = !mode; if(mode==0) pwmSetMode(PWM_MODE_BAL); else pwmSetMode(PWM_MODE_MS); pwmWrite(PWMpin, duty); break; case 3: // Change the range. (number of steps for duty cycle) printf("\n\n\n Enter Range: "); scanf("%d", &range); pwmSetRange(range); // Default 1024 (unsigned int) pwmWrite(PWMpin, duty); break; case 4: // Change the clock. printf("\n\n\n Enter Clock: "); scanf("%d", &clock); pwmSetClock(clock); // Default 32 (int) pwmWrite(PWMpin, duty); break; case 5: // Set the duty cycle. printf("\n\n\n Enter Duty Cycle: "); scanf("%d", &duty); pwmWrite(PWMpin, duty); break; case 6: // Quiet, set duty cycle to zero. duty = 0; pwmWrite(PWMpin, duty); break; } } } /********************************************************************* * main() function *********************************************************************/ int main(void) { wiringPiSetup(); pinMode (PWMpin, PWM_OUTPUT); menu(); return 0; }
