Quick Start Guide for FREQM - Basic

In this use case, the Frequency Meter (FREQM) module is configured for:

• The FREQM peripheral will not be stopped in standby sleep mode.

This use case will read measurement data in polling mode repeatly. After reading a data, the board LED will be toggled.

Setup

Prerequisites

There are no special setup requirements for this use-case.

Code

Copy-paste the following setup code to your user application:

/* FREQM module software instance (must not go out of scope while in use) */
static struct freqm_module freqm_instance;

void configure_freqm(void)
{
    /* Create a new configuration structure for the FREQM settings
     * and fill with the default module settings. */
    struct freqm_config config_freqm;
    freqm_get_config_defaults(&config_freqm);

    /* Alter any FREQM configuration settings here if required */

    /* Initialize FREQM with the user settings */
    freqm_init(&freqm_instance, FREQM, &config_freqm);
}

Add to user application initialization (typically the start of main()):

    system_init();
    configure_freqm();
    freqm_enable(&freqm_instance);

Workflow

1. Create an FREQM device instance struct, which will be associated with a FREQM peripheral hardware instance.

   static struct freqm_module freqm_instance;

   Note

   Device instance structures shall never go out of scope when in use.

2. Create a new function configure_freqm(), which will be used to configure the overall FREQM peripheral.

   void configure_freqm(void)

3. Create an FREQM peripheral configuration structure that will be filled out to set the module configuration.

       struct freqm_config config_freqm;

4. Fill the FREQM peripheral configuration structure with the default module configuration values.

       freqm_get_config_defaults(&config_freqm);

5. Initialize the FREQM peripheral and associate it with the software instance structure that was defined previously.

       freqm_init(&freqm_instance, FREQM, &config_freqm);

6. Enable the now initialized FREQM peripheral.

       freqm_enable(&freqm_instance);

Implementation

Code

Copy-paste the following code to your user application:

    uint32_t measure_result;
    enum freqm_status status;

    freqm_start_measure(&freqm_instance);
    while ((status = freqm_get_result_value(&freqm_instance, &measure_result))
            == FREQM_STATUS_MEASURE_BUSY) {
    };
    switch(status) {
        case FREQM_STATUS_MEASURE_DONE:
            LED_On(LED_0_PIN);
            while (true) {
            }
        case FREQM_STATUS_CNT_OVERFLOW:
            freqm_clear_overflow(&freqm_instance);
            while (true) {
                LED_Toggle(LED_0_PIN);
                volatile uint32_t delay = 50000;
                while(delay--) {
                }
            }
        default:
            Assert(false);
            break;
    }

Workflow

1. Start FREQM measurement and wait until measure done then read result data.

       freqm_start_measure(&freqm_instance);
       while ((status = freqm_get_result_value(&freqm_instance, &measure_result))
               == FREQM_STATUS_MEASURE_BUSY) {
       };

2. The board LED is on to indicate a measurement data is read.

           case FREQM_STATUS_MEASURE_DONE:
               LED_On(LED_0_PIN);
               while (true) {
               }

3. The board LED is toggle to indicate measurement is overflow.

           case FREQM_STATUS_CNT_OVERFLOW:
               freqm_clear_overflow(&freqm_instance);
               while (true) {
                   LED_Toggle(LED_0_PIN);
                   volatile uint32_t delay = 50000;
                   while(delay--) {
                   }
               }