Save and restore for deep sleep

examples/deep_sleep_in_c/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.5)
+include($ENV{IDF_PATH}/tools/cmake/project.cmake)
+
+# Update the below line to match the path to the ttn-esp32 library,
+# e.g. list(APPEND EXTRA_COMPONENT_DIRS "/Users/me/Documents/ttn-esp32")
+list(APPEND EXTRA_COMPONENT_DIRS "../..")
+
+#add_definitions(-DLMIC_ENABLE_event_logging=1)
+
+project(deep_sleep)

examples/deep_sleep_in_c/main/CMakeLists.txt

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+idf_component_register(
+    SRCS "main.c"
+    INCLUDE_DIRS "."
+    REQUIRES ttn-esp32)

examples/deep_sleep_in_c/main/main.c

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+/*******************************************************************************
+ * 
+ * ttn-esp32 - The Things Network device library for ESP-IDF / SX127x
+ * 
+ * Copyright (c) 2021 Manuel Bleichenbacher
+ * 
+ * Licensed under MIT License
+ * https://opensource.org/licenses/MIT
+ *
+ * Sample program (in C) sending messages and going to deep sleep in-between.
+ *******************************************************************************/
+
+#include "freertos/FreeRTOS.h"
+#include "esp_event.h"
+#include "driver/gpio.h"
+#include "nvs_flash.h"
+#include "esp_log.h"
+#include "esp_sleep.h"
+
+#include "ttn.h"
+
+// NOTE:
+// The LoRaWAN frequency and the radio chip must be configured by running 'idf.py menuconfig'.
+// Go to Components / The Things Network, select the appropriate values and save.
+
+// Copy the below hex strings from the TTN console (Applications > Your application > End devices
+// > Your device > Activation information)
+
+// AppEUI (sometimes called JoinEUI)
+const char *appEui = "????????????????";
+// DevEUI
+const char *devEui = "????????????????";
+// AppKey
+const char *appKey = "????????????????????????????????";
+
+// Pins and other resources
+#define TTN_SPI_HOST      HSPI_HOST
+#define TTN_SPI_DMA_CHAN  1
+#define TTN_PIN_SPI_SCLK  5
+#define TTN_PIN_SPI_MOSI  27
+#define TTN_PIN_SPI_MISO  19
+#define TTN_PIN_NSS       18
+#define TTN_PIN_RXTX      TTN_NOT_CONNECTED
+#define TTN_PIN_RST       14
+#define TTN_PIN_DIO0      26
+#define TTN_PIN_DIO1      35
+
+#define TX_INTERVAL 60 // in sec
+static uint8_t msgData[] = "Hello, world";
+
+
+void app_main(void)
+{
+    esp_err_t err;
+    // Initialize the GPIO ISR handler service
+    err = gpio_install_isr_service(ESP_INTR_FLAG_IRAM);
+    ESP_ERROR_CHECK(err);
+    
+    // Initialize the NVS (non-volatile storage) for saving and restoring the keys
+    err = nvs_flash_init();
+    ESP_ERROR_CHECK(err);
+
+    // Initialize SPI bus
+    spi_bus_config_t spi_bus_config = {
+        .miso_io_num = TTN_PIN_SPI_MISO,
+        .mosi_io_num = TTN_PIN_SPI_MOSI,
+        .sclk_io_num = TTN_PIN_SPI_SCLK,
+        .quadwp_io_num = -1,
+        .quadhd_io_num = -1
+    }; 
+    err = spi_bus_initialize(TTN_SPI_HOST, &spi_bus_config, TTN_SPI_DMA_CHAN);
+    ESP_ERROR_CHECK(err);
+
+    // Initialize TTN
+    ttn_init();
+
+    // Configure the SX127x pins
+    ttn_configure_pins(TTN_SPI_HOST, TTN_PIN_NSS, TTN_PIN_RXTX, TTN_PIN_RST, TTN_PIN_DIO0, TTN_PIN_DIO1);
+
+    // The below line can be commented after the first run as the data is saved in NVS
+    ttn_provision(devEui, appEui, appKey);
+
+    // ttn_set_adr_enabled(false);
+    // ttn_set_data_rate(TTN_DR_US915_SF7);
+    // ttn_set_max_tx_pow(14);
+
+    if (ttn_resume_after_deep_sleep()) {
+        printf("Resumed from deep sleep.\n");
+    
+    } else {
+
+        printf("Joining...\n");
+        if (ttn_join())
+        {
+            printf("Joined.\n");
+        }
+        else
+        {
+            printf("Join failed. Goodbye\n");
+            return;
+        }
+    }
+
+    printf("Sending message...\n");
+    ttn_response_code_t res = ttn_transmit_message(msgData, sizeof(msgData) - 1, 1, false);
+    printf(res == TTN_SUCCESSFUL_TRANSMISSION ? "Message sent.\n" : "Transmission failed.\n");
+
+    // Wait until TTN communication is idle and save state
+    ttn_wait_for_idle();
+    ttn_prepare_for_deep_sleep();
+
+    // Schedule wake up
+    esp_sleep_enable_timer_wakeup(TX_INTERVAL * 1000000LL);
+
+    printf("Going to deep sleep...\n");
+    esp_deep_sleep_start();
+}