210 lines
7.5 KiB
C
210 lines
7.5 KiB
C
/* Pulse counter module - Example
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For other examples please check:
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https://github.com/espressif/esp-idf/tree/master/examples
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This example code is in the Public Domain (or CC0 licensed, at your option.)
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Unless required by applicable law or agreed to in writing, this
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software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
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CONDITIONS OF ANY KIND, either express or implied.
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*/
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#include <stdio.h>
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#include "freertos/FreeRTOS.h"
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#include "freertos/portmacro.h"
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#include "freertos/task.h"
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#include "freertos/queue.h"
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#include "driver/periph_ctrl.h"
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#include "driver/ledc.h"
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#include "driver/gpio.h"
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#include "driver/pcnt.h"
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#include "esp_attr.h"
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#include "esp_log.h"
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#include "soc/gpio_sig_map.h"
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/**
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* TEST CODE BRIEF
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*
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* Use PCNT module to count rising edges generated by LEDC module.
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*
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* Functionality of GPIOs used in this example:
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* - GPIO18 - output pin of a sample 1 Hz pulse generator,
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* - GPIO4 - pulse input pin,
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* - GPIO5 - control input pin.
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*
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* Load example, open a serial port to view the message printed on your screen.
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*
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* To do this test, you should connect GPIO18 with GPIO4.
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* GPIO5 is the control signal, you can leave it floating with internal pull up,
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* or connect it to ground. If left floating, the count value will be increasing.
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* If you connect GPIO5 to GND, the count value will be decreasing.
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*
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* An interrupt will be triggered when the counter value:
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* - reaches 'thresh1' or 'thresh0' value,
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* - reaches 'l_lim' value or 'h_lim' value,
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* - will be reset to zero.
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*/
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#define PCNT_TEST_UNIT PCNT_UNIT_0
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#define PCNT_H_LIM_VAL 10
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#define PCNT_L_LIM_VAL -10
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#define PCNT_THRESH1_VAL 5
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#define PCNT_THRESH0_VAL -5
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#define PCNT_INPUT_SIG_IO 4 // Pulse Input GPIO
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#define PCNT_INPUT_CTRL_IO 5 // Control GPIO HIGH=count up, LOW=count down
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#define LEDC_OUTPUT_IO 18 // Output GPIO of a sample 1 Hz pulse generator
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xQueueHandle pcnt_evt_queue; // A queue to handle pulse counter events
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/* A sample structure to pass events from the PCNT
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* interrupt handler to the main program.
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*/
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typedef struct {
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int unit; // the PCNT unit that originated an interrupt
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uint32_t status; // information on the event type that caused the interrupt
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} pcnt_evt_t;
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/* Decode what PCNT's unit originated an interrupt
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* and pass this information together with the event type
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* the main program using a queue.
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*/
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static void IRAM_ATTR pcnt_example_intr_handler(void *arg)
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{
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uint32_t intr_status = PCNT.int_st.val;
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int i;
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pcnt_evt_t evt;
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portBASE_TYPE HPTaskAwoken = pdFALSE;
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for (i = 0; i < PCNT_UNIT_MAX; i++) {
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if (intr_status & (BIT(i))) {
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evt.unit = i;
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/* Save the PCNT event type that caused an interrupt
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to pass it to the main program */
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evt.status = PCNT.status_unit[i].val;
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PCNT.int_clr.val = BIT(i);
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xQueueSendFromISR(pcnt_evt_queue, &evt, &HPTaskAwoken);
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if (HPTaskAwoken == pdTRUE) {
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portYIELD_FROM_ISR();
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}
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}
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}
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}
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/* Configure LED PWM Controller
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* to output sample pulses at 1 Hz with duty of about 10%
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*/
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static void ledc_init(void)
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{
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// Prepare and then apply the LEDC PWM timer configuration
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ledc_timer_config_t ledc_timer;
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ledc_timer.speed_mode = LEDC_HIGH_SPEED_MODE;
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ledc_timer.timer_num = LEDC_TIMER_1;
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ledc_timer.duty_resolution = LEDC_TIMER_10_BIT;
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ledc_timer.freq_hz = 1; // set output frequency at 1 Hz
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ledc_timer_config(&ledc_timer);
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// Prepare and then apply the LEDC PWM channel configuration
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ledc_channel_config_t ledc_channel;
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ledc_channel.speed_mode = LEDC_HIGH_SPEED_MODE;
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ledc_channel.channel = LEDC_CHANNEL_1;
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ledc_channel.timer_sel = LEDC_TIMER_1;
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ledc_channel.intr_type = LEDC_INTR_DISABLE;
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ledc_channel.gpio_num = LEDC_OUTPUT_IO;
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ledc_channel.duty = 100; // set duty at about 10%
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ledc_channel_config(&ledc_channel);
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}
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/* Initialize PCNT functions:
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* - configure and initialize PCNT
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* - set up the input filter
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* - set up the counter events to watch
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*/
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static void pcnt_example_init(void)
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{
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/* Prepare configuration for the PCNT unit */
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pcnt_config_t pcnt_config = {
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// Set PCNT input signal and control GPIOs
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.pulse_gpio_num = PCNT_INPUT_SIG_IO,
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.ctrl_gpio_num = PCNT_INPUT_CTRL_IO,
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.channel = PCNT_CHANNEL_0,
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.unit = PCNT_TEST_UNIT,
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// What to do on the positive / negative edge of pulse input?
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.pos_mode = PCNT_COUNT_INC, // Count up on the positive edge
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.neg_mode = PCNT_COUNT_DIS, // Keep the counter value on the negative edge
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// What to do when control input is low or high?
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.lctrl_mode = PCNT_MODE_REVERSE, // Reverse counting direction if low
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.hctrl_mode = PCNT_MODE_KEEP, // Keep the primary counter mode if high
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// Set the maximum and minimum limit values to watch
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.counter_h_lim = PCNT_H_LIM_VAL,
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.counter_l_lim = PCNT_L_LIM_VAL,
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};
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/* Initialize PCNT unit */
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pcnt_unit_config(&pcnt_config);
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/* Configure and enable the input filter */
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pcnt_set_filter_value(PCNT_TEST_UNIT, 100);
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pcnt_filter_enable(PCNT_TEST_UNIT);
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/* Set threshold 0 and 1 values and enable events to watch */
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pcnt_set_event_value(PCNT_TEST_UNIT, PCNT_EVT_THRES_1, PCNT_THRESH1_VAL);
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pcnt_event_enable(PCNT_TEST_UNIT, PCNT_EVT_THRES_1);
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pcnt_set_event_value(PCNT_TEST_UNIT, PCNT_EVT_THRES_0, PCNT_THRESH0_VAL);
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pcnt_event_enable(PCNT_TEST_UNIT, PCNT_EVT_THRES_0);
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/* Enable events on zero, maximum and minimum limit values */
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pcnt_event_enable(PCNT_TEST_UNIT, PCNT_EVT_ZERO);
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pcnt_event_enable(PCNT_TEST_UNIT, PCNT_EVT_H_LIM);
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pcnt_event_enable(PCNT_TEST_UNIT, PCNT_EVT_L_LIM);
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/* Initialize PCNT's counter */
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pcnt_counter_pause(PCNT_TEST_UNIT);
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pcnt_counter_clear(PCNT_TEST_UNIT);
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/* Register ISR handler and enable interrupts for PCNT unit */
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pcnt_isr_register(pcnt_example_intr_handler, NULL, 0, NULL);
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pcnt_intr_enable(PCNT_TEST_UNIT);
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/* Everything is set up, now go to counting */
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pcnt_counter_resume(PCNT_TEST_UNIT);
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}
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void app_main()
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{
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/* Initialize LEDC to generate sample pulse signal */
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ledc_init();
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/* Initialize PCNT event queue and PCNT functions */
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pcnt_evt_queue = xQueueCreate(10, sizeof(pcnt_evt_t));
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pcnt_example_init();
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int16_t count = 0;
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pcnt_evt_t evt;
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portBASE_TYPE res;
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while (1) {
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/* Wait for the event information passed from PCNT's interrupt handler.
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* Once received, decode the event type and print it on the serial monitor.
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*/
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res = xQueueReceive(pcnt_evt_queue, &evt, 1000 / portTICK_PERIOD_MS);
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if (res == pdTRUE) {
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pcnt_get_counter_value(PCNT_TEST_UNIT, &count);
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printf("Event PCNT unit[%d]; cnt: %d\n", evt.unit, count);
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if (evt.status & PCNT_STATUS_THRES1_M) {
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printf("THRES1 EVT\n");
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}
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if (evt.status & PCNT_STATUS_THRES0_M) {
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printf("THRES0 EVT\n");
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}
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if (evt.status & PCNT_STATUS_L_LIM_M) {
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printf("L_LIM EVT\n");
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}
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if (evt.status & PCNT_STATUS_H_LIM_M) {
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printf("H_LIM EVT\n");
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}
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if (evt.status & PCNT_STATUS_ZERO_M) {
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printf("ZERO EVT\n");
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}
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} else {
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pcnt_get_counter_value(PCNT_TEST_UNIT, &count);
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printf("Current counter value :%d\n", count);
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}
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}
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}
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