upm/src/o2/o2.c
Jon Trulson e7c80217c2 C examples: move mraa_init() calls out of C examples and into C drivers.
Signed-off-by: Jon Trulson <jtrulson@ics.com>
2016-09-28 17:34:42 -06:00

140 lines
3.6 KiB
C

/*
* Author: Noel Eck <noel.eck@intel.com>
* Copyright (c) 2015 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.
*/
#include <string.h>
#include <stdlib.h>
#include "o2.h"
o2_context o2_init(int16_t pin)
{
// make sure MRAA is initialized
int mraa_rv;
if ((mraa_rv = mraa_init()) != MRAA_SUCCESS)
{
printf("%s: mraa_init() failed (%d).\n", __FUNCTION__, mraa_rv);
return NULL;
}
o2_context dev = (o2_context)malloc(sizeof(struct _o2_context));
if(dev == NULL) return NULL;
/* Init aio pin */
dev->aio = mraa_aio_init(pin);
if(dev->aio == NULL) {
free(dev);
return NULL;
}
/* Set defaults */
dev->m_aRef = 5.0;
dev->m_offset = 0.0;
dev->m_scale = 1.0;
return dev;
}
void o2_close(o2_context dev)
{
mraa_aio_close(dev->aio);
free(dev);
}
upm_result_t o2_set_aref(const o2_context dev, float aref)
{
dev->m_aRef = aref;
return UPM_SUCCESS;
}
float o2_get_aref(const o2_context dev)
{
return dev->m_aRef;
}
upm_result_t o2_set_offset(const o2_context dev, float offset)
{
dev->m_offset = offset;
return UPM_SUCCESS;
}
float o2_get_offset(const o2_context dev)
{
return dev->m_offset;
}
upm_result_t o2_set_scale(const o2_context dev, float scale)
{
dev->m_scale = scale;
return UPM_SUCCESS;
}
float o2_get_scale(const o2_context dev)
{
return dev->m_scale;
}
upm_result_t o2_get_counts(const o2_context dev, int *value)
{
/* Read counts */
*value = mraa_aio_read(dev->aio);
if (*value < 0) return UPM_ERROR_OPERATION_FAILED;
return UPM_SUCCESS;
}
upm_result_t o2_get_raw_volts(const o2_context dev, float *value)
{
/* Read normalized adc value */
*value = mraa_aio_read_float(dev->aio);
if (*value < 0.0) return UPM_ERROR_OPERATION_FAILED;
/* Convert normalized value to voltage via aRef */
*value *= dev->m_aRef;
return UPM_SUCCESS;
}
upm_result_t o2_get_value(const o2_context dev, float *value)
{
/* Read normalized value */
*value = mraa_aio_read_float(dev->aio);
if (*value < 0.0)
return UPM_ERROR_OPERATION_FAILED;
/* Apply raw scale */
*value *= dev->m_scale;
/* Convert to %oxygen
Datasheet for grove o2 shows a linear response for the sensor. Assuming
20.5% oxygen @ 25 celsius, with an gain = 1 + 12k/100 = 121, a
dynamic range of 0->25% oxygen, and opamp rails of 0->3.3v (the grove o2
sensor uses a high-accuracy 3.3v regulator),
*/
*value *= 25 * dev->m_aRef/3.3;
*value += dev->m_offset;
return UPM_SUCCESS;
}