RISCV-ULP: Add DS18B20 1wire RISCV-ULP example

2025-08-24 09:30:15 +00:00 · 2021-06-23 14:54:36 +08:00
parent 67743ac444
commit 386739595f
38 changed files with 369 additions and 25 deletions
--- a/examples/system/ulp_fsm/ulp/main/ulp_example_main.c
+++ b/examples/system/ulp_fsm/ulp/main/ulp_example_main.c
@@ -0,0 +1,120 @@
+/* ULP Example
+
+   This example code is in the Public Domain (or CC0 licensed, at your option.)
+
+   Unless required by applicable law or agreed to in writing, this
+   software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+   CONDITIONS OF ANY KIND, either express or implied.
+*/
+
+#include <stdio.h>
+#include "esp_sleep.h"
+#include "nvs.h"
+#include "nvs_flash.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 "esp32/ulp.h"
+#include "ulp_main.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);
+static void update_pulse_count(void);
+
+void app_main(void)
+{
+    esp_sleep_wakeup_cause_t cause = esp_sleep_get_wakeup_cause();
+    if (cause != ESP_SLEEP_WAKEUP_ULP) {
+        printf("Not ULP wakeup, initializing ULP\n");
+        init_ulp_program();
+    } else {
+        printf("ULP wakeup, saving pulse count\n");
+        update_pulse_count();
+    }
+
+    printf("Entering deep sleep\n\n");
+    ESP_ERROR_CHECK( esp_sleep_enable_ulp_wakeup() );
+    esp_deep_sleep_start();
+}
+
+static void init_ulp_program(void)
+{
+    esp_err_t err = ulp_load_binary(0, ulp_main_bin_start,
+            (ulp_main_bin_end - ulp_main_bin_start) / sizeof(uint32_t));
+    ESP_ERROR_CHECK(err);
+
+    /* GPIO used for pulse counting. */
+    gpio_num_t gpio_num = GPIO_NUM_0;
+    int rtcio_num = rtc_io_number_get(gpio_num);
+    assert(rtc_gpio_is_valid_gpio(gpio_num) && "GPIO used for pulse counting must be an RTC IO");
+
+    /* Initialize some variables used by ULP program.
+     * Each 'ulp_xyz' variable corresponds to 'xyz' variable in the ULP program.
+     * These variables are declared in an auto generated header file,
+     * 'ulp_main.h', name of this file is defined in component.mk as ULP_APP_NAME.
+     * These variables are located in RTC_SLOW_MEM and can be accessed both by the
+     * ULP and the main CPUs.
+     *
+     * Note that the ULP reads only the lower 16 bits of these variables.
+     */
+    ulp_debounce_counter = 3;
+    ulp_debounce_max_count = 3;
+    ulp_next_edge = 0;
+    ulp_io_number = rtcio_num; /* map from GPIO# to RTC_IO# */
+    ulp_edge_count_to_wake_up = 10;
+
+    /* Initialize selected GPIO as RTC IO, enable input, disable pullup and pulldown */
+    rtc_gpio_init(gpio_num);
+    rtc_gpio_set_direction(gpio_num, RTC_GPIO_MODE_INPUT_ONLY);
+    rtc_gpio_pulldown_dis(gpio_num);
+    rtc_gpio_pullup_dis(gpio_num);
+    rtc_gpio_hold_en(gpio_num);
+
+    /* Disconnect GPIO12 and GPIO15 to remove current drain through
+     * pullup/pulldown resistors.
+     * GPIO12 may be pulled high to select flash voltage.
+     */
+    rtc_gpio_isolate(GPIO_NUM_12);
+    rtc_gpio_isolate(GPIO_NUM_15);
+    esp_deep_sleep_disable_rom_logging(); // suppress boot messages
+
+    /* Set ULP wake up period to T = 20ms.
+     * Minimum pulse width has to be T * (ulp_debounce_counter + 1) = 80ms.
+     */
+    ulp_set_wakeup_period(0, 20000);
+
+    /* Start the program */
+    err = ulp_run(&ulp_entry - RTC_SLOW_MEM);
+    ESP_ERROR_CHECK(err);
+}
+
+static void update_pulse_count(void)
+{
+    const char* namespace = "plusecnt";
+    const char* count_key = "count";
+
+    ESP_ERROR_CHECK( nvs_flash_init() );
+    nvs_handle_t handle;
+    ESP_ERROR_CHECK( nvs_open(namespace, NVS_READWRITE, &handle));
+    uint32_t pulse_count = 0;
+    esp_err_t err = nvs_get_u32(handle, count_key, &pulse_count);
+    assert(err == ESP_OK || err == ESP_ERR_NVS_NOT_FOUND);
+    printf("Read pulse count from NVS: %5d\n", pulse_count);
+
+    /* ULP program counts signal edges, convert that to the number of pulses */
+    uint32_t pulse_count_from_ulp = (ulp_edge_count & UINT16_MAX) / 2;
+    /* In case of an odd number of edges, keep one until next time */
+    ulp_edge_count = ulp_edge_count % 2;
+    printf("Pulse count from ULP: %5d\n", pulse_count_from_ulp);
+
+    /* Save the new pulse count to NVS */
+    pulse_count += pulse_count_from_ulp;
+    ESP_ERROR_CHECK(nvs_set_u32(handle, count_key, pulse_count));
+    ESP_ERROR_CHECK(nvs_commit(handle));
+    nvs_close(handle);
+    printf("Wrote updated pulse count to NVS: %5d\n", pulse_count);
+}