02_advanced_example.c

/*************************************************************************/
#include "argus.h"
 // additional #includes ...
 
#include "driver/irq.h" // declaration of IRQ_LOCK/UNLOCK()
 
/*!***************************************************************************
 *  Global measurement data ready event counter.
 *
 *  Determines the number of measurement data ready events happened and thus
 *  the number of timer the #Argus_EvaluateData function must be called to
 *  free API internal date structures that buffer the raw sensor readout data.
 *
 *  The #Argus_EvaluateData function must be called outside of the interrupt
 *  callback scope (i.e. from the main thread/task) to avoid huge delays due
 *  to the heavy data evaluation.
 *
 *  Note that the #Argus_EvaluateData function must be called once for each
 *  callback event since it clears the internal state of the raw data buffer.
 *  If not called, the API gets stuck waiting for the raw data buffer to be
 *  freed and ready to be filled with new measurement data.
 *
 *  In automatic measurement mode, i.e. if the measurements are automatically
 *  triggered on a time based schedule from the periodic interrupt timer (PIT),
 *  the callback may occur faster than the #Argus_EvaluateData function gets
 *  called from the main thread/task. This usually happens at high frame rates
 *  or too much CPU load on the main thread/task. In that case, the API delays
 *  new measurements until the previous buffers are cleared. Since the API
 *  contains two distinct raw data buffers, this counter raises up to 2 in the
 *  worst case scenario.
 *****************************************************************************/
static volatile uint8_t myDataReadyEvents = 0;
 
/*!***************************************************************************
 * @brief   Creates and initializes a new device instance.
 *
 * @param   slave The SPI slave identifier number that is passed to the S2PI
 *                layers by the API whenever it calls a function.
 *
 * @return  The pointer to the handle of the created device instance. Used to
 *          identify the calling instance in case of multiple devices.
 *****************************************************************************/
static argus_hnd_t* InitializeDevice(s2pi_slave_t slave)
{
    /* The API module handle that contains all data definitions that is
     * required within the API module for the corresponding hardware device.
     * Every call to an API function requires the passing of a pointer to this
     * data structure. */
    argus_hnd_t * device = Argus_CreateHandle();
    HandleError(device ? STATUS_OK : ERROR_FAIL, true, "Argus_CreateHandle failed!");
 
    /* Initialize the API with the dedicated default measurement mode.
     * This implicitly calls the initialization functions
     * of the underlying API modules.
     *
     * The second parameter is stored and passed to all function calls
     * to the S2PI module. This piece of information can be utilized in
     * order to determine the addressed SPI slave and enabled the usage
     * of multiple devices on a single SPI peripheral.
     *
     * Also note the #Argus_InitMode alternative that uses a third
     * parameter to choose the measurement mode: see the #argus_mode_t
     * enumeration for more information on available measurement modes. */
    status_t status = Argus_Init(device, slave);
    HandleError(status, true, "Argus_Init failed!");
 
    /* Adjust additional configuration parameters by invoking the dedicated API methods.
     * Note: The maximum frame rate is limited by the amount of data sent via UART.
     *       See #PrintResults function for more information. */
    status = Argus_SetConfigurationFrameTime(device, 100000); // 0.1 second = 10 Hz
    HandleError(status, true, "Argus_SetConfigurationFrameTime failed!");
 
    return device;
}
 
/*!***************************************************************************
 * @brief   Measurement data ready callback function.
 *
 * @param   status The measurement/device status from the last measurement cycle.
 *
 * @param   device The pointer to the handle of the calling API instance. Used to
 *                 identify the calling instance in case of multiple devices.
 *
 * @return  Returns the \link #status_t status\endlink (#STATUS_OK on success).
 *****************************************************************************/
static status_t MeasurementReadyCallback(status_t status, argus_hnd_t * device)
{
    (void)device; // unused in this example...
 
    HandleError(status, false, "Measurement Ready Callback received error!");
 
    /* Count the data ready events, i.e. the number of times the
     * Argus_EvaluateData function must be called from main thread.
     *
     * Note: Since only a single device is used, the device parameter
     *       can be ignored. In case of multiple device, the device
     *       parameter determines the calling device instance.
     *
     * Note: Do not call the Argus_EvaluateMeasurement method
     *       from within this callback since it is invoked in
     *       a interrupt service routine and should return as
     *       soon as possible. */
    myDataReadyEvents++;
 
    return STATUS_OK;
}
 
/*!***************************************************************************
 * @brief   Prints measurement results via UART.
 *
 * @details Prints some measurement data via UART in the following format:
 *
 *          ```
 *          123.456789 s; Range: 123456 mm;  Amplitude: 1234 LSB; Quality: 100;  Status: 0
 *          ```
 *
 * @param   res A pointer to the latest measurement results structure.
 *****************************************************************************/
static void PrintResults(argus_results_t const * res)
{
    /* Print the recent measurement results:
     * 1. Time stamp in seconds since the last MCU reset.
     * 2. Range in mm (converting the Q9.22 value to mm).
     * 3. Amplitude in LSB (converting the UQ12.4 value to LSB).
     * 4. Signal Quality in % (100% = good signal).
     * 5. Status (0: OK, <0: Error, >0: Warning.
     *
     * Note: Sending data via UART creates a large delay which might prevent
     *       the API from reaching the full frame rate. This example sends
     *       approximately 80 characters per frame at 115200 bps which limits
     *       the max. frame rate of 144 fps:
     *       115200 bps / 10 [bauds-per-byte] / 80 [bytes-per-frame] = 144 fps */
    print("%4d.%06d s; Range: %5d mm;  Amplitude: %4d LSB;  Quality: %3d;  Status: %d\n",
          res->TimeStamp.sec,
          res->TimeStamp.usec,
          res->Bin.Range / (Q9_22_ONE / 1000),
          res->Bin.Amplitude / UQ12_4_ONE,
          res->Bin.SignalQuality,
          res->Status);
}
 
/*!***************************************************************************
 * @brief   Prints information about the initialized devices.
 *
 * @param   device The pointer to the device handler.
 *****************************************************************************/
static void PrintDeviceInfo(argus_hnd_t * device)
{
    /* Print some information about current API and connected device. */
    const uint32_t value = Argus_GetAPIVersion();
    const uint8_t a = (uint8_t)((value >> 24) & 0xFFU);
    const uint8_t b = (uint8_t)((value >> 16) & 0xFFU);
    const uint8_t c = (uint8_t)(value & 0xFFFFU);
    const uint32_t id = Argus_GetChipID(device);
    const char * m = Argus_GetModuleName(device);
 
    print("\n##### AFBR-S50 API - Advanced Example #########################\n"
          "  API Version: v%d.%d.%d\n"
          "  Chip ID:     %d\n"
          "  Module:      %s\n"
          "###############################################################\n\n",
          a, b, c, id, m);
}
 
/*!***************************************************************************
 * @brief   Application entry point for the simple example.
 *
 * @details The main function of the advanced example, called after startup code
 *          and hardware initialization.
 *
 *          This function will never be exited!
 *****************************************************************************/
void main(void)
{
    HardwareInit(); // defined elsewhere
 
    status_t status = STATUS_OK;
 
    /* Instantiate and initialize the device handlers. */
    argus_hnd_t * device = InitializeDevice(SPI_SLAVE);
 
    /* Print a device information message. */
    PrintDeviceInfo(device);
 
    /* Start the measurement timers within the API module.
     * The callback is invoked every time a measurement has been finished.
     * The callback is used to schedule the data evaluation routine to the
     * main thread by the user.
     * Note that the timer based measurement is not implemented for multiple
     * instance yet! */
    status = Argus_StartMeasurementTimer(device, &MeasurementReadyCallback);
    HandleError(status, true, "Argus_StartMeasurementTimer failed!");
 
    /* The program loop ... */
    for (;;)
    {
        /* Check if new measurement data is ready. */
        if (myDataReadyEvents)
        {
            IRQ_LOCK();
            myDataReadyEvents--;
            IRQ_UNLOCK();
 
            /* The measurement data structure. */
            argus_results_t res;
 
            /* Evaluate the raw measurement results. */
            status = Argus_EvaluateData(device, &res);
            HandleError(status, false, "Argus_EvaluateData failed!");
 
            /* Use the obtain results, e.g. print via UART. */
            PrintResults(&res);
        }
    }
}