Measuring 1hz to 1Mhz Input frequency on up to 6 GPIOs with maximum possible high accuracy.

[frogrammer]

My board is nRF5340Dk with NCS 2.6.1 and toolchain 2.6.1.

At this development stage I want to measure continuously incoming frequency ranging from 1Hz to 1MHz with high accuracy possible. I have tried looking into some previous similar question and implemented the code from that project on to my project but I could not get past the NRF_PPI section, which I believe now is NRF_DPPI for nrf5340 boards. But how do I implement  NRF_DPPI without extensively changing existing code? Because the way NRF_PPI was used is not similar to NRF_DPPI.

Is there a best way to measure up to 6 frequencies through GPIOS?

This is the current code :

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#include <stdbool.h>

#include <stdint.h>

#include <stdio.h>

#include <string.h>

#include <zephyr/kernel.h>

#include <zephyr/device.h>

#include <zephyr/sys/printk.h>

#include <helpers/nrfx_gppi.h>

#include <nrfx_timer.h>

#include <nrfx_gpiote.h>

#include <nrfx_dppi.h>

#define FREQ_MEASURE_PIN 7

uint32_t time = 1; // timer time in seconds

static void timer_init()

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#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <string.h>

#include <zephyr/kernel.h>

#include <zephyr/device.h>
#include <zephyr/sys/printk.h>

#include <helpers/nrfx_gppi.h>
#include <nrfx_timer.h>
#include <nrfx_gpiote.h>
#include <nrfx_dppi.h>



#define FREQ_MEASURE_PIN 7
uint32_t time = 1; // timer time in seconds

static void timer_init()
{
  uint32_t counter; 
  counter = (16000000 >> 8)*time;
  NRF_TIMER1->TASKS_STOP = 1;
  NRF_TIMER1->MODE = TIMER_MODE_MODE_Timer;
  NRF_TIMER1->PRESCALER = 8;	// f_hck / 2^8 
  NRF_TIMER1->CC[0] = counter;	
  NRF_TIMER1->BITMODE = (TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos);	
  NRF_TIMER1->TASKS_CLEAR = 1;
  NRF_TIMER1->INTENSET = (TIMER_INTENSET_COMPARE0_Enabled << TIMER_INTENSET_COMPARE0_Pos);
  NRF_TIMER1->EVENTS_COMPARE[0] = 0;
}

static void counter_init()
{
  NRF_TIMER2->TASKS_STOP = 1;	
  NRF_TIMER2->MODE = TIMER_MODE_MODE_Counter;
  NRF_TIMER2->BITMODE = (TIMER_BITMODE_BITMODE_32Bit << TIMER_BITMODE_BITMODE_Pos);
  NRF_TIMER2->TASKS_CLEAR = 1;
  NRF_TIMER2->EVENTS_COMPARE[0] = 0;
}

static void gpiote_init(uint32_t pin)
{
  NRF_GPIOTE->CONFIG[0] = 0x01 << 0;             // MODE: Event
  NRF_GPIOTE->CONFIG[0] |= pin << 8;			      // Pin number
  NRF_GPIOTE->CONFIG[0] |= NRF_GPIOTE_POLARITY_LOTOHI	<< 16; // Event rising edge 	
}

static void ppi_timer_stop_counter_init()
{
  NRF_DPPI->CHEN |= 1 << 0;
  *(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_TIMER1->EVENTS_COMPARE[0];
  *(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_STOP;
  NRF_DPPI->CHENSET |= 1 << 0;
}

static void ppi_gpiote_counter_init()
{
  NRF_DPPI->CHEN |= 1 << 1;
  *(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_GPIOTE->EVENTS_IN[0];
  *(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_COUNT;
  NRF_DPPI->CHENSET |= 1 << 1;
}

int main()
{
    // Start clock for accurate frequencies
    NRF_CLOCK->TASKS_HFCLKSTART = 1; 
    // Wait for clock to start
    while(NRF_CLOCK->EVENTS_HFCLKSTARTED == 0);

    printk("Timer Test");
    NVIC_EnableIRQ(TIMER1_IRQn);
    NVIC_SetPriority(TIMER1_IRQn, 3);	

    nrf_gpio_cfg_input(FREQ_MEASURE_PIN, NRF_GPIO_PIN_NOPULL);

    counter_init();
    timer_init();
    gpiote_init(FREQ_MEASURE_PIN);
    ppi_gpiote_counter_init();
    ppi_timer_stop_counter_init();

    NRF_TIMER1->TASKS_START = 1;
    NRF_TIMER2->TASKS_START = 1;
}

void TIMER1_IRQHandler(void) 
{
  if (NRF_TIMER1->EVENTS_COMPARE[0] != 0)
  {
      //nrf_drv_gpiote_out_toggle(LED_GREEN);
      NRF_TIMER1->EVENTS_COMPARE[0] = 0;
      NRF_TIMER2->TASKS_CAPTURE[0] = 1;
                  
      printk("%u Hz", NRF_TIMER2->CC[0]*time);

      NRF_TIMER1->TASKS_CLEAR = 1;
      NRF_TIMER2->TASKS_CLEAR = 1;	
                                  
      NRF_TIMER2->TASKS_START = 1;			
    }
}

and prj.conf

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CONFIG_GPIO=y

CONFIG_LOG=y

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CONFIG_GPIO=y
CONFIG_LOG=y

This code/project primarily has been taken from this question on devzone which was running on nRF52840 and a different SDK.

I have issues in 

static void ppi_timer_stop_counter_init() and in 

static void ppi_gpiote_counter_init() 

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static void ppi_timer_stop_counter_init()

{

NRF_DPPI->CHEN |= 1 << 0;

*(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_TIMER1->EVENTS_COMPARE[0];

*(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_STOP;

NRF_DPPI->CHENSET |= 1 << 0;

}

static void ppi_gpiote_counter_init()

{

NRF_DPPI->CHEN |= 1 << 1;

*(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_GPIOTE->EVENTS_IN[0];

*(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_COUNT;

NRF_DPPI->CHENSET |= 1 << 1;

}

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static void ppi_timer_stop_counter_init()
{
  NRF_DPPI->CHEN |= 1 << 0;
  *(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_TIMER1->EVENTS_COMPARE[0];
  *(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_STOP;
  NRF_DPPI->CHENSET |= 1 << 0;
}

static void ppi_gpiote_counter_init()
{
  NRF_DPPI->CHEN |= 1 << 1;
  *(&(NRF_DPPI->CH[1].EEP)) = (uint32_t)&NRF_GPIOTE->EVENTS_IN[0];
  *(&(NRF_DPPI->CH[1].TEP)) = (uint32_t)&NRF_TIMER2->TASKS_COUNT;
  NRF_DPPI->CHENSET |= 1 << 1;
}

Although, I have changed the name, NRF_PPI to NRF_DPPI in my code to check if that works, it doesn't and I have no clue how to implement that EEP or TEP.

It would be helpful to get some directions on these requirements.