Hey,
I thought I will make in a short time a function that calculates the PWM duty cycle of a fixed PWM signal.
The following steps I made to implement this:
-Start an interrupt for the right port and pin
-If rising edge occurs start a LPTMR timer and set the interrupt to falling edge
-If falling edge stop the timer and calculate the duty cycle
My problem is that I use whole PORTA as interrupt. Therefore I tried "PORT_SetPinInterruptConfig" and "FGPIO_PortGetInterruptFlags" to read out the right pin. This code beneath doesn't work at all. It will not enter the IRQ. In "fsl_GPIO" you have functions with PORT and functions with PINS that is really confusing. When do you use what?
My setup is:
-NXP MKE14F512
-FreeRTOS operating system
-MCUXpresso 10.1.1
The used code is below and I also added some output data as attached file.
The function "Read_Pump" is called every 5 seconds
//Read in the PWM duty cycle of the pump and give back the duty cycle in %
/*-Set the interrupt of the pump pin to rising edge
*-Enable the interrupt of port A
*-In interrupt handler save timer value
*-If pulse was not started start timer and set pin interrupt to falling edge, remember timer has started
*-If pulse was started calculate duty cycle and store value
*/
void Read_Pump(void)
{
//Set the pump port pin to interrupt rising edge
PORT_SetPinInterruptConfig(GPIOA, 37U, kPORT_InterruptRisingEdge);
//Enable the interrupt
EnableIRQ(PORTA_IRQn);
}
void IRQ_HANDLER_PORT_A(void)
{
//uint32_t Interrept_Flags_A = FGPIO_PortGetInterruptFlags(PORTA_BASE_ADDRESS);
uint32_t Timer_Value = LPTMR_GetCurrentTimerCount(DEMO_LPTMR_BASE);
uint32_t flags = GPIO_GetPinsInterruptFlags(GPIOA);
DisableIRQ(PORTA_IRQn);
/* Clear external interrupt flag. */
GPIO_ClearPinsInterruptFlags(GPIOA, 37U << 7U);
if(Pulse_Started)
{
//Stop the timer
LPTMR_StopTimer(DEMO_LPTMR_BASE); //Stop the time
//Calculate the PWM duty cycle in %
Timer_Value = Timer_Value * 78125; //LPO clock is 128Khz 1/128Khz = 7,8125 us
Timer_Value = Timer_Value/1333333; //75Hz period time 1/75 = 13333,33 us
SUS_Data.Pump_In_Duty = Timer_Value; //Store PWM duty to local variable
Pulse_Started = false;
}
else
{
//start the timer and switch the interrupt flag to failing edge and make Pulse_Started True
LPTMR_StartTimer(DEMO_LPTMR_BASE); //Start the timer
PORT_SetPinInterruptConfig(GPIOA, 37U, kPORT_InterruptFallingEdge);
Pulse_Started = true;
EnableIRQ(PORTA_IRQn);
}
}
