int main(int argc, char **argv) {
setvbuf(stdout, NULL, _IONBF, 0); // needed to print to the command line
int x;
int a;
// initialise the servo pi on I2C address 0x40 with the Output Enable pin enabled.
// Check the returned value to ensure the Servo Pi initialised correctly
a = servopi_init(0x40, 1);
if (a != 0) {
if (a == 1) {
printf("Error enabling GPIO Pin");
}
if (a == 2) {
printf("Error setting GPIO Pin direction");
}
return (0);
}
//Set PWM frequency to 60 Hz and enable the output
set_pwm_freq(60, 0x40);
output_enable();
while (1) {
set_pwm(1, 0, servoMin, 0x40); // set the pwm width to servoMin
usleep(500000); // sleep 0.5 seconds
set_pwm(1, 0, servoMed, 0x40); // set the pwm width to servoMed
usleep(500000); // sleep 0.5 seconds
set_pwm(1, 0, servoMax, 0x40); // set the pwm width to servoMax
usleep(500000); // sleep 0.5 seconds
}
return (0);
}
int main(int argc, char **argv) {
setvbuf(stdout, NULL, _IONBF, 0); // needed to print to the command line
int x;
int a;
// initialise the servo pi on I2C address 0x40 with the Output Enable pin enabled.
// Check the returned value to ensure the Servo Pi initialised correctly
a = servopi_init(0x40, 1);
if (a != 0){
if (a == 1){
printf("Error enabling GPIO Pin");
}
if (a == 2){
printf("Error setting GPIO Pin direction");
}
return (0);
}
//Set PWM frequency to 1 Khz and enable the output
set_pwm_freq(1000, 0x40);
output_enable();
while (1) {
for (x = 1; x <= 4095; x = x + 5) {
set_pwm(1, 0, x, 0x40); // set the pwm width to x
}
for (x = 4095; x >= 0; x = x - 5) {
set_pwm(1, 0, x, 0x40); // set the pwm width to x
}
}
return (0);
}
static int __init pwm_start(void) {
int ret = 0;
struct clk *timer_fclk;
uint32_t gt_rate;
printk(KERN_INFO "Loading PWM Module... \n");
// request any timer
timer_ptr = omap_dm_timer_request();
if(timer_ptr == NULL){
// no timers available
printk("pwm module: No more gp timers available, bailing out\n");
return -1;
}
// set the clock source to the system clock
ret = omap_dm_timer_set_source(timer_ptr, OMAP_TIMER_SRC_SYS_CLK);
if(ret) {
printk("pwm module: could not set source\n");
return -1;
}
// set prescalar to 1:1
omap_dm_timer_set_prescaler(timer_ptr, 0);
// figure out what IRQ our timer triggers
timer_irq = omap_dm_timer_get_irq(timer_ptr);
// install our IRQ handler for our timer
ret = request_irq(timer_irq, timer_irq_handler, IRQF_DISABLED | IRQF_TIMER , "pwm", timer_irq_handler);
if(ret){
printk("pwm module: request_irq failed (on irq %d), bailing out\n", timer_irq);
return ret;
}
// get clock rate in Hz and add it to struct
timer_fclk = omap_dm_timer_get_fclk(timer_ptr);
gt_rate = clk_get_rate(timer_fclk);
pwm_data_ptr.timer_rate = gt_rate;
// set preload, and autoreload
// we set it to a default of 1kHz
set_pwm_freq(1000);
// setup timer to trigger IRQ on the overflow
omap_dm_timer_set_int_enable(timer_ptr, OMAP_TIMER_INT_OVERFLOW);
// start the timer
omap_dm_timer_start(timer_ptr);
// done!
printk("pwm module: GP Timer initialized and started (%lu Hz, IRQ %d)\n", (long unsigned)gt_rate, timer_irq);
// setup a GPIO
pwm_setup_pin(38);
pwm_data_ptr.pin = 38;
set_pwm_dutycycle(1,150);
// return success
return 0;
}
