833bac569c
There is a small typo in examples/c/pwm.c, examples/c/spi.c. Should read `repeatedly` rather than `repeately`.
108 lines
2.2 KiB
C
108 lines
2.2 KiB
C
/*
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* Author: Thomas Ingleby <thomas.c.ingleby@intel.com>
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* Contributors: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
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* Copyright (c) 2014 Intel Corporation.
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*
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* SPDX-License-Identifier: MIT
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*
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* Example usage: Generates PWM signal of period 200us with variable dutycyle
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* repeatedly. Press Ctrl+C to exit
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*/
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/* standard headers */
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#include <signal.h>
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#include <stdlib.h>
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#include <unistd.h>
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/* mraa header */
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#include "mraa/pwm.h"
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/* PWM declaration */
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#define PWM 3
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/* PWM period in us */
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#define PWM_FREQ 200
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volatile sig_atomic_t flag = 1;
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void
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sig_handler(int signum)
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{
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if (signum == SIGINT) {
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fprintf(stdout, "Exiting...\n");
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flag = 0;
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}
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}
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int
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main(void)
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{
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mraa_result_t status = MRAA_SUCCESS;
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mraa_pwm_context pwm;
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float value = 0.0f;
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float output;
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/* initialize mraa for the platform (not needed most of the times) */
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mraa_init();
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//! [Interesting]
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pwm = mraa_pwm_init(PWM);
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if (pwm == NULL) {
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fprintf(stderr, "Failed to initialize PWM\n");
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mraa_deinit();
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return EXIT_FAILURE;
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}
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/* set PWM period */
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status = mraa_pwm_period_us(pwm, PWM_FREQ);
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if (status != MRAA_SUCCESS) {
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goto err_exit;
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}
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/* enable PWM */
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status = mraa_pwm_enable(pwm, 1);
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if (status != MRAA_SUCCESS) {
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goto err_exit;
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}
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while (flag) {
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value = value + 0.01f;
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/* write PWM duty cyle */
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status = mraa_pwm_write(pwm, value);
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if (status != MRAA_SUCCESS) {
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goto err_exit;
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}
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usleep(50000);
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if (value >= 1.0f) {
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value = 0.0f;
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}
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/* read PWM duty cyle */
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output = mraa_pwm_read(pwm);
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fprintf(stdout, "PWM value is %f\n", output);
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}
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/* close PWM */
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mraa_pwm_close(pwm);
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//! [Interesting]
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/* deinitialize mraa for the platform (not needed most of the times) */
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mraa_deinit();
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return EXIT_SUCCESS;
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err_exit:
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mraa_result_print(status);
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/* close PWM */
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mraa_pwm_close(pwm);
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/* deinitialize mraa for the platform (not needed most of the times) */
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mraa_deinit();
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return EXIT_FAILURE;
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}
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