ESP32 Forum

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#include <stdio.h>
#include "esp_sleep.h"
#include "soc/rtc_cntl_reg.h"
#include "soc/sens_reg.h"
#include "soc/rtc_periph.h"
#include "driver/gpio.h"
#include "driver/rtc_io.h"
#include "ulp_riscv.h"
#include "ulp_main.h"
#include "freertos/FreeRTOS.h"
#include "freertos/task.h"
#include "esp_log.h"

extern const uint8_t ulp_main_bin_start[] asm("_binary_ulp_main_bin_start");
extern const uint8_t ulp_main_bin_end[] asm("_binary_ulp_main_bin_end");

static void init_ulp_program(void);

#define TAG "ULP-Test"

void app_main(void)
{
  ESP_LOGI(TAG, "Starting ESP32-S3 ULP test");

    ESP_LOGI(TAG, "Starting ULP program...");
    init_ulp_program();

  ESP_LOGI(TAG, "Waiting for ULP data...");
  uint32_t Cycles=0;
  for (;;)
  {
    if (ulp_DataReady)
    {
      Cycles++;
      ulp_DataReady = 0;
      ESP_LOGI(TAG, "ESP32 Cycles: %lu ULP Cycles: %lu", Cycles, ulp_Cycles);
    }
    vTaskDelay(100 / portTICK_PERIOD_MS);
  }
}

static void init_ulp_program(void)
{
  esp_err_t err = ulp_riscv_load_binary(ulp_main_bin_start, (ulp_main_bin_end - ulp_main_bin_start));
  ESP_ERROR_CHECK(err);

  /* The first argument is the period index, which is not used by the ULP-RISC-V timer
   * The second argument is the period in microseconds, which gives a wakeup time period of: 20ms
   */
  ulp_set_wakeup_period(0, 20000);

  /* Start the program */
  err = ulp_riscv_run();
  ESP_ERROR_CHECK(err);
}

Code: Select all

#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include "ulp_riscv.h"
#include "ulp_riscv_utils.h"
#include "ulp_riscv_gpio.h"
#include "esp_err.h"

#define BOARD_LED GPIO_NUM_17

/* this variable will be exported as a public symbol, visible from main CPU: */

uint32_t DataReady = 0;
uint32_t Cycles = 0;

int main(void)
{
  DataReady=false;
  ulp_riscv_gpio_init(BOARD_LED);
  ulp_riscv_gpio_output_enable(BOARD_LED);
  ulp_riscv_gpio_set_output_mode(BOARD_LED, RTCIO_MODE_OUTPUT);

  int flag = 0;
  for (;;)
  {
    flag = 1 - flag;
    ulp_riscv_gpio_output_level(GPIO_NUM_17, flag);
    Cycles++;
    DataReady = 1;
    ulp_riscv_delay_cycles(1000000 * ULP_RISCV_CYCLES_PER_US); // 1s Pause
  }
  /* ulp_riscv_halt() is called automatically when main exits */
  return 0;
}

Code: Select all

void static inline ulp_riscv_delay_cycles(uint32_t cycles)
{
    uint32_t start = ULP_RISCV_GET_CCOUNT();
	/* Off with an estimate of cycles in this function to improve accuracy */
    uint32_t end = start + cycles - 20;

    while (ULP_RISCV_GET_CCOUNT()  < end) {
        /* Wait */
    }
}

Code: Select all

#pragma once

#ifdef __cplusplus
extern "C" {
#endif

#include "sdkconfig.h"
#include <stdint.h>
#include "ulp_riscv_utils.h"

void static inline delay(uint32_t cycles)
{
  uint32_t mark = ULP_RISCV_GET_CCOUNT();
  uint32_t interval;
  do
  {
    interval = ULP_RISCV_GET_CCOUNT() - mark; // underflow is well defined
  } while (interval < cycles);
}

#ifdef __cplusplus
}
#endif