diff options
Diffstat (limited to 'peripheral/examples/mraa/gpio_output/OutputGPIO.cpp')
-rw-r--r-- | peripheral/examples/mraa/gpio_output/OutputGPIO.cpp | 127 |
1 files changed, 127 insertions, 0 deletions
diff --git a/peripheral/examples/mraa/gpio_output/OutputGPIO.cpp b/peripheral/examples/mraa/gpio_output/OutputGPIO.cpp new file mode 100644 index 0000000..31b63d5 --- /dev/null +++ b/peripheral/examples/mraa/gpio_output/OutputGPIO.cpp @@ -0,0 +1,127 @@ +/* + * Copyright (C) 2015 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +/* + * This is an example to set/clear a GPIO pin using the MRAA library. + * This may be tested with any of many GPIO devices such as an LED + * directly connected to the GPIO pin and ground, + * the Grove buzzer or Grove LED board. + * + * The on-board LED on the Edison Arudino expansion board may be + * accessed with Digital I/O 13 (mapped from Linux GPIO 243): + * example-gpio-output -p 13 -s + * + * See the following link for a table to map from the numbers on the + * board silk screen to the libmraa GPIO numbers: + * https://learn.sparkfun.com/tutorials/installing-libmraa-on-ubilinux-for-edison + */ +#include <getopt.h> +#include <stdio.h> +#include <stdlib.h> + +#include <mraa.h> + +// Structure to hold the decoded command line options +struct pgm_options { + int pin; + bool set; + bool clear; +}; + +// Be sure to keep the options for longopts and shortopts in the same order +// so that Usage() is correct. +static struct option longopts[] = { + {"help", no_argument, NULL, '?'}, + {"pin", no_argument, NULL, 'p'}, + {"set", no_argument, NULL, 's'}, + {"clear", no_argument, NULL, 'c'}, + {NULL, 0, NULL, 0 } +}; +static char shortopts[] = "?p:sc"; + +// Describes the options for this program. +void Usage(char *pgm_name) { + printf("Usage: %s [options...]\n", pgm_name); + printf("Manipulate a GPIO pin\n"); + printf("Options:\n"); + for (int i = 0, j = 0; longopts[i].name; i++, j++) { + if (shortopts[j] == ':') + j++; + printf(" --%-6s%s or -%c%s""\n", + longopts[i].name, + (shortopts[j+1] == ':') ? " <arg> " : "", + shortopts[j], + (shortopts[j+1] == ':') ? " <arg> " : ""); + } + return; +} + +// Processes all command line options. +// sets the options members for commnd line options +// returns (0) on success, -1 otherwise. +int ReadOpts(int argc, char **argv, struct pgm_options *options) { + int ch = 0; + + while ((ch = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) { + switch (ch) { + case 'p': + options->pin = atoi(optarg); + break; + case 's': + options->set = true; + break; + case 'c': + options->clear = true; + break; + default: + Usage(argv[0]); + return -1; + } + } + argc -= optind; + argv += optind; + + return 0; +} + +int main(int argc, char* argv[]) { + const unsigned kDefaultPinGPIO = 7; + pgm_options options = {kDefaultPinGPIO, false, false}; + + if (ReadOpts(argc, argv, &options) < 0) + return 1; + + mraa_init(); + mraa_gpio_context m_gpio = mraa_gpio_init(options.pin); + if (!m_gpio) { + fprintf(stderr, "Unable to initialize GPIO, invalid pin number?\n"); + return 1; + } + mraa_gpio_dir(m_gpio, MRAA_GPIO_OUT); + + if (options.set) + mraa_gpio_write(m_gpio, 1); + + // If both options were specified, wait a few seconds before clearing + if (options.clear && options.set) + sleep(5); + + if (options.clear) + mraa_gpio_write(m_gpio, 0); + + mraa_gpio_close(m_gpio); + return 0; +} |