osd-contiki/examples/osd/pwm-example/resource_led_pwm.c

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/**
* \file
* Resource for hardware timer handling
* \author
* Ralf Schlatterbeck <rsc@runtux.com>
*
* \brief get/put pwm for LED pin
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "contiki.h"
#include "jsonparse.h"
/* Only coap 13 for now */
#include "er-coap-13.h"
#include "hw_timer.h"
#include "generic_resource.h"
#define DEBUG 1
#if DEBUG
#define PRINTF(...) printf(__VA_ARGS__)
#else
#define PRINTF(...)
#endif
static uint16_t max_ticks = 0, pwm = 0;
void led_pwm_init (void)
{
int8_t result = hwtimer_pwm_ini (3, 20, HWT_PWM_PHASE_CORRECT, 0);
PRINTF ("HWTIMER init: %d\n", result);
max_ticks = hwtimer_pwm_max_ticks (3);
pwm = max_ticks / 2;
hwtimer_set_pwm (3, HWT_CHANNEL_C, pwm);
hwtimer_pwm_inverse (3, HWT_CHANNEL_C);
DDRE |= (1<<PINE5);
}
void pwm_from_string (const char *name, const char *s)
{
pwm = atoi (s);
if (pwm > max_ticks) {
pwm = max_ticks;
}
PRINTF ("Setting: %d (max=%d)\n", pwm, max_ticks);
hwtimer_pwm_inverse (3, HWT_CHANNEL_C);
DDRE |= (1<<PINE5);
hwtimer_set_pwm (3, HWT_CHANNEL_C, pwm);
PRINTF
( "TCNT3: %04X TCCR3A: %04X TCCR3B: %04X TCCR3C: %04X OCR3C: %04X\n"
, TCNT3, TCCR3A, TCCR3B, TCCR3C, OCR3C
);
}
size_t pwm_to_string (const char *n, uint8_t is_json, char *buf, size_t bufsize)
{
return snprintf (buf, bufsize, "%d", pwm);
}
GENERIC_RESOURCE \
( led_pwm, METHOD_GET | METHOD_PUT
, "led/pwm"
, LED PWM
, duty-cycle
, pwm_from_string
, pwm_to_string
);