File content as of revision 6:be7123d400ae:

/*
 * mbed Library / Frequency Counter using GPS 1PPS gate pulse
 *      Frequency Counter program
 *      Only for ST DISCO-F746NG and Nucleo-F411RE+F446RE
 *
 * Copyright (c) 2014,'15,'16 Kenji Arai / JH1PJL
 *  http://www.page.sannet.ne.jp/kenjia/index.html
 *  http://mbed.org/users/kenjiArai/
 *      Started:    October   18th, 2014
 *      Revised:    January    1st, 2015
 *      Re-started: June      25th, 2016    ported from F411 board
 *      Re-started: October    5th, 2016    Change board -> DISCO-F746NG
 *      Re-started: October   17th, 2016    Continue F746 and back to F411
 *      Revised:    November  13th, 2016
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER  LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
 * OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

/*
--------------------------------------------------------------------------------
********* Frequency Counter Functions *********
Mesurement frequency:  1Hz to 100MHz
Extended range:        Up to 1GHz (1/10 prescaler) or more over (1/20)
Gate time:             1 sec to 4095sec (extend to more if RAM is avairable)
1 PPS:                 GPS receiver(u-blux7/NEO-7) with an external antenna
Additional function:   Reciprocal measurement (less tha 10KHz)

********* Hardware Configration (Board is only ST DISCO-F746NG) *********
frequency input:       PC_6(D1) & PB10(No assign to connector!)
GPS 1PPS:              PA_15(D9), PB_8(D15) & PC_7(D0)

********* Hardware Configration (Board is only ST Nucleo-F411RE) *********
RESTRICTION -> Max input freqency is 48MHz due to system clock limitation
frequency input:       PA_8(D7) & PA_0(A0)
GPS 1PPS:              PA_9(D8), PB_0(A3) & PA_1(A1)
--------------------------------------------------------------------------------
*/

#ifndef     MBED_FRQ_CUNTR
#define     MBED_FRQ_CUNTR

#include    "mbed.h"

#define     DEBUG   0  // use Communication with PC(UART)

typedef union
{
    struct {
        uint64_t    f_1sec_dt;
    };
    struct {
        uint32_t    freq_dt;
        uint16_t    f_sw_dt;
        uint16_t    t_cnt;
    };
} freq_one;

namespace Frequency_counter
{

/** Frequency Counter program
 *  Only for ST DISCO-F746NG Board（Nucleo-F411RE & F446RE also)
 *
 * @code
 * #include "mbed.h"
 * #include "fc_GPS1PPS.h"
 *
 * using namespace Frequency_counter;
 *
 * //----F746---- max input f=100MHz
 * // frequency input  -> PC_6 & PA15(for reciprocal)
 * // GPS 1PPS -> PB_8,PC_7 & PB_10(for reciprocal)
 * //----F411---- max input f=48MHz
 * //----F446---- max input f=90MHz
 * // frequency input  -> PA_8 & PA_0(for reciprocal)
 * // GPS 1PPS -> PA_9, PB_0 & PA_1(for reciprocal)
 *
 * FRQ_CUNTR    fc;
 *
 * int main() {
 *   double   frequency = 0;
 *   while(true) {
 *      while (fc.status_freq_update() == 0) {;}
 *      frequency = fc.read_freq_data(); // 1sec gate
 *      printf("FREQ. = %11.1f\r\n", frequency);
 *   }
 * }
 * @endcode
 */

class FRQ_CUNTR
{

public:

    /** Configure counter
      * @param none
      */
    FRQ_CUNTR(void);

    /** Read new frequency data (gate time = 1sec)
      * @param none
      * @return frequency data
      */
    double read_freq_data(void);

    /** Read new frequency data with specific gate time
      * @param gate time [sec] (1 sec to over 1 hour(F746) or 17 minutes)
      * @return frequency data
      */
    double read_freq_w_gate_time(uint16_t gt);

    /** Read status (new frequency data is available or not)
      * @param none
      * @return !=0: new data is avairable, 0: not yet
      */
    uint32_t status_freq_update(void);

    /** Reset buffered data
      * @param none
      * @return none
      */
    void reset_buffered_data(void);

    /** Reciprocal measurement (Step1)
      * preparation for Reciprocal measurement
      * @param none
      * @return none
      */
    void recipro_start_measure(void);

    /** Reciprocal measurement (Step2)
      * check frequency input as IC trigger
      * @param none
      * @return 1: done, 0: not yet
      */
    uint32_t recipro_check_trigger(void);

    /** Reciprocal measurement (Step3)
      * read period data
      * @param none
      * @return frequency data
      */
    uint32_t recipro_read_data(void);

    /** Reciprocal measurement (Step4)
      * read period data
      * @param gate time [sec] (1 sec to over 1 hour)
      * @return time base clock frequency data
      */
    uint32_t recipro_base_clk_data(uint16_t gt);

    /** "DEBUG PURPOSE" function
      * Check input frequency on TIM8+4 or TIM1+3
      * print internal data (need to define "DEBUG")
      * @param gate time e.g. 1sec = 1.0f
      * @return frequency data
      */
    uint32_t debug_read_input_frequency(double gatetime);

    /** "DEBUG PURPOSE" function
      * Check input frequency on TIM2
      * print internal data (need to define "DEBUG")
      * @param gate time e.g. 1sec = 1.0f
      * @return frequency data
      */
    uint32_t debug_read_base_clock_frequency(double gatetime);

    /** "DEBUG PURPOSE" function
      * print internal data (No need to define "DEBUG")
      * @param none
      * @return none (just print tha data)
      */     
    void debug_printf_all_buffer(void);

protected:
    void     start_action(void);        // Start trigger for reciprocal
    void     initialize_TIMxPy(void);   // Initialize Timer_x + _y (16+16bit)
    void     initialize_TIMz(void);     // Initialize Timer_z (32bit)
    uint64_t get_diff(uint64_t new_dt, uint64_t old_dt);

private:
    double   newest_frequency;

};

/*
    Interrupt handler does NOT work following code
    NVIC_SetVector(TIM4_IRQn, (uint32_t)FRQ_CUNTR::irq_ic_TIMxPy);
    From this reason, I wrote below code and set interrupt handler
    out side "FRQ_CUNTR" class
    NVIC_SetVector(TIM4_IRQn, (uint32_t)irq_ic_TIMxPy);
 */
    void irq_ic_TIMxPy(void);  // TIM4（F746) or TIM3（F411) IC Interrupt
    void irq_ic_TIMz(void);    // TIM2（F746 & F411) IC Interrupt

}   // Frequency_counter

#endif  // MBED_FRQ_CUNTR