osd-contiki/examples/osd/pwm-example/resource_led_pwm.c
Ralf Schlatterbeck 5991c3e3db Initial implementation of avr hardware timer
Mainly for PWM use for now.
With example to set the LED to different brightness via COAP.
We switch the LED with 50 kHz (20µs) in this example.
2014-06-22 13:32:05 +02:00

175 lines
4.7 KiB
C

/**
* \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"
/* Error-handling macro */
# define BYE(_exp, _tag) \
do { \
PRINTF("Expect "_exp": %d\n",_tag); \
success=0; \
goto bye; \
} while(0)
#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);
}
RESOURCE \
( led_pwm, METHOD_GET | METHOD_PUT
, "led/pwm"
, "title=\"LED PWM\";rt=\"led pwm\""
);
void
led_pwm_handler
( void* request
, void* response
, uint8_t *buffer
, uint16_t preferred_size
, int32_t *offset
)
{
int success = 1;
int i;
char temp[100];
int index = 0;
int length = 0;
int tag = 0;
const uint8_t *bytes = NULL;
size_t len = 0;
int n_acc = 0;
const uint16_t *accept = NULL;
uint16_t a_ctype = REST.type.APPLICATION_JSON;
uint16_t c_ctype = REST.get_header_content_type (request);
/* Seems like accepted type is currently unsupported? */
n_acc = REST.get_header_accept (request, &accept);
for (i=0; i<n_acc; i++) {
if ( accept [i] == REST.type.TEXT_PLAIN
|| accept [i] == REST.type.APPLICATION_JSON
)
{
a_ctype = accept [i];
break;
}
}
switch(REST.get_method_type(request)) {
case METHOD_GET:
// TEXT format
if (a_ctype == REST.type.TEXT_PLAIN) {
index += sprintf (temp + index, "%d\n", pwm);
} else { // jSON Format
index += sprintf
( temp + index
,"{\n \"pwm\" : \"%d\"\n}\n"
, pwm
);
}
length = strlen(temp);
memcpy (buffer, temp, length);
REST.set_header_content_type (response, a_ctype);
REST.set_response_payload (response, buffer, length);
break;
case METHOD_PUT:
if ((len = coap_get_payload(request, &bytes))) {
PRINTF ("PUT: len: %d, %s\n", len, (char *)bytes);
if (c_ctype == REST.type.TEXT_PLAIN) {
temp [sizeof (temp) - 1] = 0;
strncpy (temp, (char *)bytes, MIN (len + 1, sizeof (temp) - 1));
} else { // jSON Format
struct jsonparse_state state;
struct jsonparse_state *parser = &state;
jsonparse_setup (parser, (char *)bytes, len);
if ((tag = jsonparse_next (parser)) != JSON_TYPE_OBJECT) {
BYE ("OBJECT", tag);
}
if ((tag = jsonparse_next (parser)) != JSON_TYPE_PAIR_NAME) {
BYE ("PAIR_NAME", tag);
}
while (jsonparse_strcmp_value (parser, "pwm") != 0) {
tag = jsonparse_next (parser);
if (tag != JSON_TYPE_PAIR) {
BYE ("PAIR", tag);
}
tag = jsonparse_next (parser);
tag = jsonparse_next (parser);
if (tag != ',') {
BYE (",", tag);
}
tag = jsonparse_next (parser);
if (tag != JSON_TYPE_PAIR_NAME) {
BYE ("PAIR_NAME", tag);
}
}
tag = jsonparse_next (parser);
if (tag != JSON_TYPE_PAIR) {
BYE ("PAIR", tag);
}
tag = jsonparse_next (parser);
if (tag != JSON_TYPE_STRING) {
BYE ("STRING", tag);
}
jsonparse_copy_value (parser, temp, sizeof (temp));
temp [sizeof (temp) - 1] = 0;
}
PRINTF ("GOT: %s\n", temp);
pwm = atoi (temp);
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
);
REST.set_response_status(response, REST.status.CHANGED);
} else {
PRINTF ("PUT: len: %d\n", len);
success = 0;
}
bye :
break;
default:
success = 0;
}
if (!success) {
REST.set_response_status(response, REST.status.BAD_REQUEST);
}
}