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dfd1eb0672
Add a new example that shows how to read a sample from an ADS7046 ADC sensor registered on the SPI bus. Signed-off-by: Niccolò Maggioni <nicco.maggioni+nuttx@gmail.com>
91 lines
3.2 KiB
C
91 lines
3.2 KiB
C
/****************************************************************************
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* apps/examples/ads7046/ads7046_main.c
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*
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* SPDX-License-Identifier: Apache-2.0
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <sys/ioctl.h>
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#include <nuttx/analog/ioctl.h>
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#include <nuttx/analog/ads7046.h>
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/****************************************************************************
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* Pre-processor Definitions
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****************************************************************************/
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/* As per the datasheet, the ADS7046 returns the following readings:
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* INPUT VOLTAGE (AINP - AINM) DESCRIPTION HEX
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* -------------------------------------- ------------------------ ---
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* <= 1 LSB Negative full-scale code 000
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* 1 LSB to 2 LSB - 001
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* V_REF / 2 to V_REF / 2 + 1 LSB Mid code 7FF
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* V_REF / 2 + 1 LSB to V_REF / 2 + 2 LSB - 800
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* >= V_REF - 1 LSB Positive full-scale code FFF
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*/
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#define SAMPLE_TO_PCT(sample) (((sample) * 100) / 0xfff)
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: ads7046_main
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****************************************************************************/
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int main(const int argc, FAR char *argv[])
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{
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UNUSED(argc);
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UNUSED(argv);
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int ret;
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int fd;
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uint16_t sample;
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fd = open(CONFIG_EXAMPLES_ADS7046_DEVPATH, O_RDONLY);
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if (fd < 0)
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{
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printf("Failed to open %s: %s (%d)\n", CONFIG_EXAMPLES_ADS7046_DEVPATH,
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strerror(errno), errno);
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return EXIT_FAILURE;
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}
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ret = ioctl(fd, ANIOC_ADS7046_READ, &sample);
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if (ret != OK)
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{
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perror("Could not ioctl fd");
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close(fd);
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return EXIT_FAILURE;
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}
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printf("ADS7046: hex=%x, dec=%"PRIu16", adc_percentage=%u%%\n",
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sample, sample, SAMPLE_TO_PCT(sample));
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close(fd);
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return EXIT_SUCCESS;
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}
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