File content as of revision 5:af9fa3d0731c:

/*
 * mbed Application program / Frequency Counter
 *
 * Copyright (c) 2014 Kenji Arai / JH1PJL
 *  http://www.page.sannet.ne.jp/kenjia/index.html
 *  http://mbed.org/users/kenjiArai/
 *      Created: October   18th, 2014
 *      Revised: October   19th, 2014
 *
 * 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.
 */

//  Include ---------------------------------------------------------------------------------------
#include "mbed.h"
#include "TextLCD.h"            // Std. lib./ LCD control
#include "freq_counter.h"

//  Definition ------------------------------------------------------------------------------------
#define USE_COM         // use Communication with PC(UART)

#ifdef USE_COM
#define BAUD(x)         pc.baud(x)
#define GETC(x)         pc.getc(x)
#define PUTC(x)         pc.putc(x)
#define PRINTF(...)     pc.printf(__VA_ARGS__)
#define READABLE(x)     pc.readable(x)
#else
#define BAUD(x)         {;}
#define GETC(x)         {;}
#define PUTC(x)         {;}
#define PRINTF(...)     {;}
#define READABLE(x)     {;}
#endif

// LPC1768 Frequency example
// Outout mbed's "PWM6" pin to 96MHZ/19 = 5.052MHz (Approx)
#define PWM_EAMPLE()    PWM6_SETCLK(19)
// Outout mbed's "PWM6" pin to 96MHZ/96 = 1.000MHz (Approx)
//#define PWM_EAMPLE()    PWM6_SETCLK(96)
  
//  Object ----------------------------------------------------------------------------------------
DigitalOut led_gate(LED1);
DigitalOut led_not_zero(LED2);
DigitalOut led_01(LED3);
DigitalOut led_10(LED4);
DigitalIn  sw_01(p19);
DigitalIn  sw_10(p20);
Serial pc(USBTX, USBRX);
I2C i2cBus(p9, p10);   // SDA, SCL
TextLCD_I2C_N lcd(&i2cBus, 0x7c, TextLCD::LCD8x2);  // LCD(Akizuki AQM0802A)
PwmOut fmclck(p21);                 // for RESERVE pin21 as PWM1[6]
F_COUNTER fc(p30);

//  RAM -------------------------------------------------------------------------------------------
float freqency;
float t_gate;
uint8_t sw;

//  ROM / Constant data ---------------------------------------------------------------------------

//  Function prototypes ---------------------------------------------------------------------------

//  Function prototypes ---------------------------------------------------------------------------

//-------------------------------------------------------------------------------------------------
//  Control Program
//-------------------------------------------------------------------------------------------------
#if defined(TARGET_LPC1768)
// Clock Output From pin21(PWM6)
// Set Clock Freq with div.
// if mbed is running at 96MHz, div is set 96 to Get 1MHz.
void PWM6_SETCLK(int div)
{
    LPC_PWM1->TCR = (1 << 1);           // 1)Reset counter, disable PWM
    LPC_SC->PCLKSEL0 &= ~(0x3 << 12);
    LPC_SC->PCLKSEL0 |= (1 << 12);      // 2)Set peripheral clock divider to /1, i.e. system clock
    LPC_PWM1->MR0 = div - 1;            // 3)Match Register 0 is shared period counter for all PWM1
    LPC_PWM1->MR6 = (div + 1)>> 1;      //
    LPC_PWM1->LER |= 1;                 // 4)Start updating at next period start
    LPC_PWM1->TCR = (1 << 0) || (1 << 3); // 5)Enable counter and PWM
}
#else
#error "No support for this CPU"
#endif

void example_freq_out(void)
{
    PWM_EAMPLE();
}

void read_sw_and_set_gate_time(void)
{
    if (sw_10) {
        led_10 = 1;
        sw = 2;
    } else {
        led_10 = 0;
        sw = 0;
    }
    if (sw_01) {
        led_01 = 1;
        sw += 1;
    } else {
        led_01 = 0;
    }
    switch (sw) {
        case 0:
            t_gate = 0.001;
            break;
        case 1:
            t_gate = 0.01;
            break;
        case 2:
            t_gate = 0.1;
            break;
        case 3:
        default:
            t_gate = 1.0;
            break;
    }
}

int main()
{
    PRINTF("Frequency Counter by JH1PJL created on "__DATE__"\r\n");
    t_gate = 1.0;
    // Initialize LCD
    lcd.locate(0, 0);    // 1st line top
    //          12345678
    lcd.printf("Fre-Cntr");
    lcd.locate(0, 1);    // 2nd line top
    //        12345678
    lcd.puts(" JH1PJL ");
    lcd.setContrast(0x16);
    wait(5.0);
    lcd.locate(0, 1);    // 2nd line top
    //        12345678
    lcd.puts("        ");
    // Set PWM for example
    example_freq_out();
    freqency = 0;
    while(true) {
        led_gate = 1;
        freqency = (float)fc.read_frequency(t_gate);
        led_gate = 0;
        wait(1.1 - t_gate);
        if (freqency == 0) {
            led_not_zero = 1;
        } else {
            led_not_zero = 0;
        }
        read_sw_and_set_gate_time();
        PRINTF("p30 f = %9.0f [Hz] gate %4.3f [Sec]\r\n", freqency/t_gate, t_gate);
        lcd.locate(0, 0);    // 1st line top
        lcd.printf("%8.0f", freqency);
        lcd.locate(0, 1);    // 2nd line top
        switch (sw) {
            case 0:
                //          12345678
                lcd.printf("x1000 Hz");
                break;
            case 1:
                //          12345678
                lcd.printf("x100  Hz");
                break;
            case 2:
                //          12345678
                lcd.printf("x10   Hz");
                break;
            case 3:
            default:
                //          12345678
                lcd.printf("x1    Hz");
                break;
        }
    }
}