cable.c

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/***************************************************************************//**
 * @file cable.c
 * @brief Cable checking functionality.
 * @version 2.1
 * @author
 *   Matthias Alleman@n
 *   Modified by Brecht Van Eeckhoudt
 *
 * ******************************************************************************
 *
 * @section Versions
 *
 *   @li v1.0: Move `checkCable` from `main.c` to this file and add battery voltage measurement logic.
 *   @li v1.1: Updated code with new DEFINE checks.
 *   @li v1.2: Moved ADC functionality to `adc.c`.
 *   @li v1.3: Changed filename to `cable.c`
 *   @li v1.4: Fixed cable checking method.
 *   @li v1.5: Moved more functionality to this file.
 *   @li v2.0: Added functionality to also send taken measurements when a cable break is
 *             detected and updated version number.
 *   @li v2.1: Updated documentation.
 *
 * ******************************************************************************
 *
 * @todo
 *   **Future improvements:**@n
 *     - Use two parallel lines who normally aren't connected and use an interrupt
 *       to detect if they broke and get connected through the water.
 *
 * ******************************************************************************
 *
 * @section License
 *
 *   **Copyright (C) 2019 - Brecht Van Eeckhoudt**
 *
 *   This program is free software: you can redistribute it and/or modify
 *   it under the terms of the **GNU General Public License** as published by
 *   the Free Software Foundation, either **version 3** of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   *A copy of the GNU General Public License can be found in the `LICENSE`
 *   file along with this source code.*
 *
 *   @n
 *
 *   Some methods use code obtained from examples from [Silicon Labs' GitHub](https://github.com/SiliconLabs/peripheral_examples).
 *   These sections are licensed under the Silabs License Agreement. See the file
 *   "Silabs_License_Agreement.txt" for details. Before using this software for
 *   any purpose, you must agree to the terms of that agreement.
 *
 ******************************************************************************/


#include <stdint.h>        /* (u)intXX_t */
#include <stdbool.h>       /* "bool", "true", "false" */
#include "em_device.h"     /* Include necessary MCU-specific header file */
#include "em_cmu.h"        /* Clock management unit */
#include "em_gpio.h"       /* General Purpose IO */

#include "cable.h"         /* Corresponding header file */
#include "pin_mapping.h"   /* PORT and PIN definitions */
#include "debug_dbprint.h" /* Enable or disable printing to UART for debugging */
#include "lora_wrappers.h" /* LoRaWAN functionality */
#include "datatypes.h"     /* Definitions of the custom data-types */


/* Local variable */
/** Keep the amount of times a message has been send to indicate the cable is broken (only send 4 messages in total) */
uint8_t cableBrokenSendTimes = 0;


/* Local prototype */
static bool checkCable_internal (void);


/**************************************************************************//**
 * @brief
 *   Method to check if the wire is broken.
 *
 * @param[in] data
 *   The struct which contains the measurements to send using LoRaWAN.
 *
 * @return
 *   @li `true` - Measurements have been send so the index has to be set back to zero.
 *   @li `false` - No LoRaWAN message has been send.
 *****************************************************************************/
bool checkCable (MeasurementData_t data)
{
    /* Check if the cable is broken */
    if (!checkCable_internal())
    {
        /* Only send a message 4 times */
        if (cableBrokenSendTimes < 4)
        {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
            dbcrit("Cable broken! Sending the data ...");
#endif /* DEBUG_DBPRINT */

            initLoRaWAN(); /* Initialize LoRaWAN functionality */

            sendCableBroken(true);  /* Send the LoRaWAN message */
            sendMeasurements(data); /* Send the measurements */

            disableLoRaWAN(); /* Disable RN2483 */

            cableBrokenSendTimes++; /* Increment the counter */

            return (true);
        }
        else
        {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
            dbcrit("Cable broken but no longer sending the data");
#endif /* DEBUG_DBPRINT */

            return (false);
        }
    }
    else
    {

#if DEBUG_DBPRINT == 1 /* DEBUG_DBPRINT */
        dbinfo("Cable still intact");
#endif /* DEBUG_DBPRINT */

        return (false);
    }
}


/**************************************************************************//**
 * @brief
 *   Method to check if the wire is broken.
 *
 * @details
 *   This method enables the necessary GPIO clocks, sets the mode of the pins,
 *   checks the connection between them and also disables them at the end.
 *
 * @note
 *   This is a static method because it's only internally used in this file
 *   and called by other methods if necessary.
 *
 * @return
 *   @li `true` - The connection is still okay.
 *   @li `false` - The connection is broken!
 *****************************************************************************/
static bool checkCable_internal (void)
{
    /* Value to eventually return */
    bool check = false;

    /* Enable necessary clocks (just in case) */
    CMU_ClockEnable(cmuClock_HFPER, true); /* GPIO is a High Frequency Peripheral */
    CMU_ClockEnable(cmuClock_GPIO, true);

    /* Change mode of first pin */
    GPIO_PinModeSet(BREAK1_PORT, BREAK1_PIN, gpioModeInput, 0);

    /* Change mode of second pin and also set it low with the last argument */
    GPIO_PinModeSet(BREAK2_PORT, BREAK2_PIN, gpioModePushPull, 0);

    /* Check the connection */
    if (!GPIO_PinInGet(BREAK1_PORT,BREAK1_PIN)) check = true;

    /* Disable the pins */
    GPIO_PinModeSet(BREAK1_PORT, BREAK1_PIN, gpioModeDisabled, 0);
    GPIO_PinModeSet(BREAK2_PORT, BREAK2_PIN, gpioModeDisabled, 0);

    return (check);
}