HomeEnergyMeter/main/pcnt_functions.c

#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "freertos/queue.h"
#include "driver/ledc.h"
#include "driver/pcnt.h"
#include "esp_attr.h"
#include "esp_log.h"
#include "config.h"
#include "pcnt_functions.h"

#include "soc/dport_reg.h"

#ifdef CCFG_PCNT

/** Electric meter:
 * 10000 impulses per kWh
 * Some normal max number could be 120 kWh/24h = 5 kWh/hour = 50000 pulses/hour = 833 pulses/min = 14 pulses/sec
 * 
 * Counter is 16 bit signed = Max 32768 pulses = Will NOT work for one hour !!!!!
 * So we need some other way of counting higher numbers that will last for one h
 * Probably we need to use interrupts !
 */


// Example-code: https://github.com/espressif/esp-idf/blob/master/examples/peripherals/pcnt/pulse_count_event/main/pcnt_event_example_main.c

// Counts interrupts that occus every 32K Pulses
// The counter register is 16 bit signed so we count to 32K before doing an interrupt
// This equals to 32kWH consumed energy (at 1000 pulses per kWh)
static uint32_t Counter_32K_Pulses = 0;

static const int pcntUnit = PCNT_UNIT_0;

static void pCntMonitorTask(void *pvParameters);

static double getkWh(uint32_t *bigCnt, int32_t *cnt) {

    pcnt_intr_disable(pcntUnit);
    volatile int32_t count = DPORT_REG_READ(0x3FF57060);
    volatile uint32_t bigCounter = Counter_32K_Pulses;
    pcnt_intr_enable(pcntUnit);

    *bigCnt = bigCounter;
    *cnt = count;

    const double retVal = ((double)bigCounter*32)+((double)count / PULSES_PER_KWH);

    return retVal;
}

static void IRAM_ATTR pcnt_example_intr_handler(void *arg)
{
    Counter_32K_Pulses++;
}



void init_pcnt_unit()
{
    /* Prepare configuration for the PCNT unit */
    pcnt_config_t pcnt_config = {
        // Set PCNT input signal and control GPIOs
        .pulse_gpio_num = PCNT_INPUT_SIG_IO,
        .ctrl_gpio_num = PCNT_PIN_NOT_USED;
        .channel = PCNT_CHANNEL_0,
        .unit = pcntUnit,
        // What to do on the positive / negative edge of pulse input?
        .pos_mode = PCNT_COUNT_INC,   // Count up on the positive edge
        .neg_mode = PCNT_COUNT_DIS,   // Keep the counter value on the negative edge
        // What to do when control input is low or high?
        .lctrl_mode = PCNT_MODE_REVERSE, // Reverse counting direction if low
        .hctrl_mode = PCNT_MODE_KEEP,    // Keep the primary counter mode if high
        // Set the maximum and minimum limit values to watch
        .counter_h_lim = 32000,
        .counter_l_lim = 0,
    };
    /* Initialize PCNT unit */
    pcnt_unit_config(&pcnt_config);

    // How to read a periphial-register:
    //uint32_t c = p_pcnt_obj->hal.dev.hw.conf_unit[unit];
    //printf("Reg: %08x\n",(uint32_t)DPORT_REG_READ(0x3FF57000));

    //The length of ignored pulses is provided in APB_CLK clock cycles by calling pcnt_set_filter_value().
    //The current filter setting may be checked with pcnt_get_filter_value().
    //The APB_CLK clock is running at 80 MHz.

    /* Configure and enable the input filter */
    pcnt_set_filter_value(pcntUnit, 1023); // APB_CLK=80MHz * 1023 is filtered out = 0,0127875mS (????)
    pcnt_filter_enable(pcntUnit);

    /* Enable int on high count limit */
    pcnt_event_enable(pcntUnit, PCNT_EVT_H_LIM);

    /* Initialize PCNT's counter */
    pcnt_counter_pause(pcntUnit);
    pcnt_counter_clear(pcntUnit);

    /* Install interrupt service and add isr callback handler */
    pcnt_isr_service_install(0);
    pcnt_isr_handler_add(pcntUnit, pcnt_example_intr_handler, (void *)pcntUnit);

    /* Everything is set up, now go to counting */
    pcnt_counter_resume(pcntUnit);
}

static void pCntMonitorTask(void *pvParameters) {

    ESP_LOGI("PCNT", "pCntMonitorTask starting");

    /*
        char dataStr[100];
    double kWh = 0.0;
    uint32_t bigCnt = 0;
    int32_t cnt = 0;

        kWh = getkWh(&bigCnt, &cnt);

        sprintf(dataStr,"%.5f",kWh);

        // @TODO This is changed for testing
#ifdef MQTT_ENABLED
        sendMQTTMessage("/sensors/TEST/energy/electricalTotal", dataStr);
#endif

        ESP_LOGI("MAIN", "%.4f   %u    %d",kWh,bigCnt,cnt);


    */
}

void initPCNT() {

    init_pcnt_unit();
    ledc_init();
    xTaskCreate(pCntMonitorTask, "pCntMonitorTask", 1024*10, NULL, 2, NULL);
}


#endif