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examples: cleanup examples directory

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Following changes are done as a part of cleanup:

1. Moved the platform specific `C` examples from top level examples/
directory to platform/ subdirectory and renamed helloedison.c to
gpio_edison.c

2. C specific examples are moved to a new c/ subdirectory. As a part
of this process, examples are modified to follow same standards
and few new examples are also added.

3. Include the newly added C examples to relevant API documentation

4. Ran clang-format for all source files in c/, c++/, platform/
subdirectories

Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Brendan Le Foll <brendan.le.foll@intel.com>
This commit is contained in:
Manivannan Sadhasivam
2017-11-17 17:22:34 +05:30
committed by Brendan Le Foll
parent 3fb65de4b8
commit e562c774cf
46 changed files with 1542 additions and 1025 deletions
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224
examples/c/i2c_hmc5883l.c Normal file
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/*
* Author: Brendan Le Foll <brendan.le.foll@intel.com>
* Copyright (c) 2014 Intel Corporation.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* Example usage: Outputs X,Y,Z co-ordinates and direction recursively using
* HMC5883L. Press Ctrl+C to exit.
*
*/
/* standard headers */
#include <math.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
/* mraa header */
#include "mraa/i2c.h"
#define MAX_BUFFER_LENGTH 6
#define HMC5883L_I2C_ADDR 0x1E
/* configuration registers */
#define HMC5883L_CONF_REG_A 0x00
#define HMC5883L_CONF_REG_B 0x01
/* mode register */
#define HMC5883L_MODE_REG 0x02
/* data register */
#define HMC5883L_X_MSB_REG 0
#define HMC5883L_X_LSB_REG 1
#define HMC5883L_Z_MSB_REG 2
#define HMC5883L_Z_LSB_REG 3
#define HMC5883L_Y_MSB_REG 4
#define HMC5883L_Y_LSB_REG 5
#define DATA_REG_SIZE 6
/* status register */
#define HMC5883L_STATUS_REG 0x09
/* ID registers */
#define HMC5883L_ID_A_REG 0x0A
#define HMC5883L_ID_B_REG 0x0B
#define HMC5883L_ID_C_REG 0x0C
#define HMC5883L_CONT_MODE 0x00
#define HMC5883L_DATA_REG 0x03
/* scales */
#define GA_0_88_REG 0x00 << 5
#define GA_1_3_REG 0x01 << 5
#define GA_1_9_REG 0x02 << 5
#define GA_2_5_REG 0x03 << 5
#define GA_4_0_REG 0x04 << 5
#define GA_4_7_REG 0x05 << 5
#define GA_5_6_REG 0x06 << 5
#define GA_8_1_REG 0x07 << 5
/* digital resolutions */
#define SCALE_0_73_MG 0.73
#define SCALE_0_92_MG 0.92
#define SCALE_1_22_MG 1.22
#define SCALE_1_52_MG 1.52
#define SCALE_2_27_MG 2.27
#define SCALE_2_56_MG 2.56
#define SCALE_3_03_MG 3.03
#define SCALE_4_35_MG 4.35
#define I2C_BUS 0
volatile sig_atomic_t flag = 1;
void
sig_handler(int signum)
{
if (signum == SIGINT) {
fprintf(stdout, "Exiting...\n");
flag = 0;
}
}
int
main(void)
{
mraa_result_t status = MRAA_SUCCESS;
mraa_i2c_context i2c;
float direction = 0;
int16_t x = 0, y = 0, z = 0;
uint8_t rx_tx_buf[MAX_BUFFER_LENGTH];
/* install signal handler */
signal(SIGINT, sig_handler);
/* initialize mraa for the platform (not needed most of the times) */
mraa_init();
//! [Interesting]
i2c = mraa_i2c_init(I2C_BUS);
if (i2c == NULL) {
fprintf(stderr, "Failed to initialize I2C\n");
mraa_deinit();
return EXIT_FAILURE;
}
/* set slave address */
mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
/* set device gain */
rx_tx_buf[0] = HMC5883L_CONF_REG_B;
rx_tx_buf[1] = GA_1_3_REG;
status = mraa_i2c_write(i2c, rx_tx_buf, 2);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
status = mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
/* set continuous mode */
rx_tx_buf[0] = HMC5883L_MODE_REG;
rx_tx_buf[1] = HMC5883L_CONT_MODE;
status = mraa_i2c_write(i2c, rx_tx_buf, 2);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
while (flag) {
#if 0
int i = 0;
/*
* alternative, equivalent method which helps to understand exactly what
* the below does
*/
mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
for (i = 0; i < DATA_REG_SIZE; i++) {
mraa_i2c_read_byte_data(i2c, HMC5883L_DATA_REG+i);
}
#endif
/* select data register to read */
status = mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
status = mraa_i2c_write_byte(i2c, HMC5883L_DATA_REG);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
/* do a incremental read from the chosen address */
status = mraa_i2c_address(i2c, HMC5883L_I2C_ADDR);
if (status != MRAA_SUCCESS) {
goto err_exit;
}
/* this call behaves very similarly to the Wire receive() call */
mraa_i2c_read(i2c, rx_tx_buf, DATA_REG_SIZE);
x = (rx_tx_buf[HMC5883L_X_MSB_REG] << 8) | rx_tx_buf[HMC5883L_X_LSB_REG];
z = (rx_tx_buf[HMC5883L_Z_MSB_REG] << 8) | rx_tx_buf[HMC5883L_Z_LSB_REG];
y = (rx_tx_buf[HMC5883L_Y_MSB_REG] << 8) | rx_tx_buf[HMC5883L_Y_LSB_REG];
/* scale and calculate direction */
direction = atan2(y * SCALE_0_92_MG, x * SCALE_0_92_MG);
/* check if the signs are reversed */
if (direction < 0) {
direction += 2 * M_PI;
}
fprintf(stdout, "Compass scaled data x : %f, y : %f, z : %f\n", x * SCALE_0_92_MG,
y * SCALE_0_92_MG, z * SCALE_0_92_MG);
fprintf(stdout, "Heading : %f\n", direction * 180 / M_PI);
sleep(2);
}
/* stop i2c */
mraa_i2c_stop(i2c);
//! [Interesting]
/* deinitialize mraa for the platform (not needed most of the times) */
mraa_deinit();
return EXIT_SUCCESS;
err_exit:
mraa_result_print(status);
/* stop i2c */
mraa_i2c_stop(i2c);
/* deinitialize mraa for the platform (not needed most of the times) */
mraa_deinit();
return EXIT_FAILURE;
}