Wide Timer PWM - Servo Control - Example

/* * Code created using CCS v6 with TI compiler. Used TivaWare. * This code configures a Wide Timer to output a PWM of 50Hz. * By changing the duty it's possible to control a servo position */#define PART_TM4C123GH6PM#include <stdint.h>#include <stdbool.h>#include "stdlib.h"#include "inc/hw_ints.h"#include "inc/hw_memmap.h"#include "inc/hw_uart.h"#include "inc/hw_gpio.h"#include "inc/hw_timer.h"#include "inc/hw_types.h"#include "driverlib/pin_map.h"#include "driverlib/rom.h"#include "driverlib/rom_map.h"#include "driverlib/debug.h"#include "driverlib/systick.h"#include "driverlib/interrupt.h"#include "driverlib/sysctl.h"#include "driverlib/uart.h"#include "driverlib/udma.h"#include "driverlib/gpio.h"#include "driverlib/timer.h"#include <string.h>#define freq 50#define Period 80000000/freq#define dutyCycle1 Period-1-80000 //1ms positive width#define dutyCycle2 Period-1-160000 //2ms positive width//dutyCycle1 > dutyCycle2 uint32_t ServoWrite(uint32_t valor) { uint32_t i = 0; i = Period - ( (valor * 444) + 80000); TimerMatchSet(WTIMER0_BASE, TIMER_B, i);}int main(void) { SysCtlClockSet(SYSCTL_SYSDIV_2_5|SYSCTL_USE_PLL|SYSCTL_OSC_MAIN|SYSCTL_XTAL_16MHZ); SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOC); SysCtlDelay(3); GPIOPinConfigure(GPIO_PC5_WT0CCP1); GPIOPinTypeTimer(GPIO_PORTC_BASE, GPIO_PIN_5); SysCtlPeripheralEnable(SYSCTL_PERIPH_WTIMER0); SysCtlDelay(3); TimerConfigure(WTIMER0_BASE, TIMER_CFG_SPLIT_PAIR|TIMER_CFG_B_PWM); TimerLoadSet(WTIMER0_BASE, TIMER_B, Period-1); TimerMatchSet(WTIMER0_BASE, TIMER_B, Period-1);

/*

This sets the 10th bit in the GPTMTBMR. This makes it so the match value only updates after the next timeout

*/

HWREG(WTIMER0_BASE+TIMER_TBMR_TBMRSU) =1; TimerEnable(WTIMER0_BASE, TIMER_B); uint32_t i = 1; while(1){ for(i = 1; i < 180; i++) { //TimerDisable(WTIMER0_BASE, TIMER_B); ServoWrite(i); //TimerEnable(WTIMER0_BASE, TIMER_B); SysCtlDelay(26600); } SysCtlDelay(20000); for(i = 180-1; i > 0; i--) { //TimerDisable(WTIMER0_BASE, TIMER_B); ServoWrite(i); //TimerEnable(WTIMER0_BASE, TIMER_B); SysCtlDelay(26600); } SysCtlDelay(20000); } return 0;}