File content as of revision 1:7dde0e4d30da:

/* Timer_TPM.cpp
 * Tested with mbed board: FRDM-KL46Z
 * Author: Mark Gottscho
 * mgottscho@ucla.edu
 */

#include "mbed.h"
#include "HardwareTimer.h"
#include "Timer_TPM.h"

//Init class static variable
bool Timer_TPM::__initialized_tpm = false;
uint16_t Timer_TPM::__rolloverValue = 0xFFFF;
uint32_t Timer_TPM::__count = 0;


Timer_TPM::Timer_TPM() :
        HardwareTimer(20.8333333333) //20.833... ns per tick, roll over at maximum possible value to reduce interrupt frequency
        {   
}

Timer_TPM::~Timer_TPM() {}

void Timer_TPM::disableTimer() {
    if (!__valid)
        return;
        
    TPM0->SC = 0; //Reset TPM
    __enabled = false;
}

uint32_t Timer_TPM::getTick() {
    if (!__valid)
        return 0;
        
    //Get raw time
    __disable_irq();
    TPM0->CNT = 0; //Need to write to the TPM CNT register in order to read it (buffering)
    uint16_t tick = TPM0->CNT;
    uint32_t count = __count;
    __enable_irq();
    
    //Convert to ticks
    return (uint32_t) count * __rolloverValue + tick;
}

void Timer_TPM::__set_tpm(uint16_t count) {
    //TPM0->SC &= ~TPM_SC_CMOD_MASK; //Stop clock
    TPM0->CNT = 0; //Set the count register
    TPM0->MOD = count; //Set the modulo register
    TPM0->SC |= TPM_SC_TOIE_MASK; //Enable interrupt
    TPM0->SC |= TPM_SC_CMOD(1); //Start the timer. Timer will increment on the TPM clock edges, not an external clock
}

void Timer_TPM::__isr_tpm() {
    TPM0->SC |= TPM_SC_TOF_MASK;
    __set_tpm(__rolloverValue);
    __count++;
}