--- /dev/null
+/* ESPNOW 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.
+*/
+
+#ifndef ESPNOW_EXAMPLE_H
+#define ESPNOW_EXAMPLE_H
+
+/* ESPNOW can work in both station and softap mode. It is configured in menuconfig. */
+#if CONFIG_STATION_MODE
+#define ESPNOW_WIFI_MODE WIFI_MODE_STA
+#define ESPNOW_WIFI_IF ESP_IF_WIFI_STA
+#else
+#define ESPNOW_WIFI_MODE WIFI_MODE_AP
+#define ESPNOW_WIFI_IF ESP_IF_WIFI_AP
+#endif
+
+#define ESPNOW_QUEUE_SIZE 6
+
+#define IS_BROADCAST_ADDR(addr) (memcmp(addr, example_broadcast_mac, ESP_NOW_ETH_ALEN) == 0)
+
+typedef enum {
+ EXAMPLE_ESPNOW_SEND_CB,
+ EXAMPLE_ESPNOW_RECV_CB,
+} example_espnow_event_id_t;
+
+typedef struct {
+ uint8_t mac_addr[ESP_NOW_ETH_ALEN];
+ esp_now_send_status_t status;
+} example_espnow_event_send_cb_t;
+
+typedef struct {
+ uint8_t mac_addr[ESP_NOW_ETH_ALEN];
+ uint8_t *data;
+ int data_len;
+} example_espnow_event_recv_cb_t;
+
+typedef union {
+ example_espnow_event_send_cb_t send_cb;
+ example_espnow_event_recv_cb_t recv_cb;
+} example_espnow_event_info_t;
+
+/* When ESPNOW sending or receiving callback function is called, post event to ESPNOW task. */
+typedef struct {
+ example_espnow_event_id_t id;
+ example_espnow_event_info_t info;
+} example_espnow_event_t;
+
+enum {
+ EXAMPLE_ESPNOW_DATA_BROADCAST,
+ EXAMPLE_ESPNOW_DATA_UNICAST,
+ EXAMPLE_ESPNOW_DATA_MAX,
+};
+
+/* User defined field of ESPNOW data in this example. */
+typedef struct {
+ uint8_t type; //Broadcast or unicast ESPNOW data.
+ uint8_t state; //Indicate that if has received broadcast ESPNOW data or not.
+ uint16_t seq_num; //Sequence number of ESPNOW data.
+ uint16_t crc; //CRC16 value of ESPNOW data.
+ uint32_t magic; //Magic number which is used to determine which device to send unicast ESPNOW data.
+ uint8_t payload[0]; //Real payload of ESPNOW data.
+} __attribute__((packed)) example_espnow_data_t;
+
+/* Parameters of sending ESPNOW data. */
+typedef struct {
+ bool unicast; //Send unicast ESPNOW data.
+ bool broadcast; //Send broadcast ESPNOW data.
+ uint8_t state; //Indicate that if has received broadcast ESPNOW data or not.
+ uint32_t magic; //Magic number which is used to determine which device to send unicast ESPNOW data.
+ uint16_t count; //Total count of unicast ESPNOW data to be sent.
+ uint16_t delay; //Delay between sending two ESPNOW data, unit: ms.
+ int len; //Length of ESPNOW data to be sent, unit: byte.
+ uint8_t *buffer; //Buffer pointing to ESPNOW data.
+ uint8_t dest_mac[ESP_NOW_ETH_ALEN]; //MAC address of destination device.
+} example_espnow_send_param_t;
+
+#endif
--- /dev/null
+/* ESPNOW 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.
+*/
+
+/*
+ This example shows how to use ESPNOW.
+ Prepare two device, one for sending ESPNOW data and another for receiving
+ ESPNOW data.
+*/
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+#include <assert.h>
+#include "freertos/FreeRTOS.h"
+#include "freertos/semphr.h"
+#include "freertos/timers.h"
+#include "nvs_flash.h"
+#include "esp_event_loop.h"
+#include "tcpip_adapter.h"
+#include "esp_wifi.h"
+#include "esp_log.h"
+#include "esp_system.h"
+#include "esp_now.h"
+#include "rom/ets_sys.h"
+#include "rom/crc.h"
+#include "espnow_example.h"
+
+static const char *TAG = "espnow_example";
+
+static xQueueHandle example_espnow_queue;
+
+static uint8_t example_broadcast_mac[ESP_NOW_ETH_ALEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
+static uint16_t s_example_espnow_seq[EXAMPLE_ESPNOW_DATA_MAX] = { 0, 0 };
+
+static void example_espnow_deinit(example_espnow_send_param_t *send_param);
+
+static esp_err_t example_event_handler(void *ctx, system_event_t *event)
+{
+ switch(event->event_id) {
+ case SYSTEM_EVENT_STA_START:
+ ESP_LOGI(TAG, "WiFi started");
+ break;
+ default:
+ break;
+ }
+ return ESP_OK;
+}
+
+/* WiFi should start before using ESPNOW */
+static void example_wifi_init(void)
+{
+ tcpip_adapter_init();
+ ESP_ERROR_CHECK( esp_event_loop_init(example_event_handler, NULL) );
+ wifi_init_config_t cfg = WIFI_INIT_CONFIG_DEFAULT();
+ ESP_ERROR_CHECK( esp_wifi_init(&cfg) );
+ ESP_ERROR_CHECK( esp_wifi_set_storage(WIFI_STORAGE_RAM) );
+ ESP_ERROR_CHECK( esp_wifi_set_mode(ESPNOW_WIFI_MODE) );
+ ESP_ERROR_CHECK( esp_wifi_start());
+
+ /* In order to simplify example, channel is set after WiFi started.
+ * This is not necessary in real application if the two devices have
+ * been already on the same channel.
+ */
+ ESP_ERROR_CHECK( esp_wifi_set_channel(CONFIG_ESPNOW_CHANNEL, 0) );
+}
+
+/* ESPNOW sending or receiving callback function is called in WiFi task.
+ * Users should not do lengthy operations from this task. Instead, post
+ * necessary data to a queue and handle it from a lower priority task. */
+static void example_espnow_send_cb(const uint8_t *mac_addr, esp_now_send_status_t status)
+{
+ example_espnow_event_t evt;
+ example_espnow_event_send_cb_t *send_cb = &evt.info.send_cb;
+
+ if (mac_addr == NULL) {
+ ESP_LOGE(TAG, "Send cb arg error");
+ return;
+ }
+
+ evt.id = EXAMPLE_ESPNOW_SEND_CB;
+ memcpy(send_cb->mac_addr, mac_addr, ESP_NOW_ETH_ALEN);
+ send_cb->status = status;
+ if (xQueueSend(example_espnow_queue, &evt, portMAX_DELAY) != pdTRUE) {
+ ESP_LOGW(TAG, "Send send queue fail");
+ }
+}
+
+static void example_espnow_recv_cb(const uint8_t *mac_addr, const uint8_t *data, int len)
+{
+ example_espnow_event_t evt;
+ example_espnow_event_recv_cb_t *recv_cb = &evt.info.recv_cb;
+
+ if (mac_addr == NULL || data == NULL || len <= 0) {
+ ESP_LOGE(TAG, "Receive cb arg error");
+ return;
+ }
+
+ evt.id = EXAMPLE_ESPNOW_RECV_CB;
+ memcpy(recv_cb->mac_addr, mac_addr, ESP_NOW_ETH_ALEN);
+ recv_cb->data = malloc(len);
+ if (recv_cb->data == NULL) {
+ ESP_LOGE(TAG, "Malloc receive data fail");
+ return;
+ }
+ memcpy(recv_cb->data, data, len);
+ recv_cb->data_len = len;
+ if (xQueueSend(example_espnow_queue, &evt, portMAX_DELAY) != pdTRUE) {
+ ESP_LOGW(TAG, "Send receive queue fail");
+ free(recv_cb->data);
+ }
+}
+
+/* Parse received ESPNOW data. */
+int example_espnow_data_parse(uint8_t *data, uint16_t data_len, uint8_t *state, uint16_t *seq, int *magic)
+{
+ example_espnow_data_t *buf = (example_espnow_data_t *)data;
+ uint16_t crc, crc_cal = 0;
+
+ if (data_len < sizeof(example_espnow_data_t)) {
+ ESP_LOGE(TAG, "Receive ESPNOW data too short, len:%d", data_len);
+ return -1;
+ }
+
+ *state = buf->state;
+ *seq = buf->seq_num;
+ *magic = buf->magic;
+ crc = buf->crc;
+ buf->crc = 0;
+ crc_cal = crc16_le(UINT16_MAX, (uint8_t const *)buf, data_len);
+
+ if (crc_cal == crc) {
+ return buf->type;
+ }
+
+ return -1;
+}
+
+/* Prepare ESPNOW data to be sent. */
+void example_espnow_data_prepare(example_espnow_send_param_t *send_param)
+{
+ example_espnow_data_t *buf = (example_espnow_data_t *)send_param->buffer;
+ int i = 0;
+
+ assert(send_param->len >= sizeof(example_espnow_data_t));
+
+ buf->type = IS_BROADCAST_ADDR(send_param->dest_mac) ? EXAMPLE_ESPNOW_DATA_BROADCAST : EXAMPLE_ESPNOW_DATA_UNICAST;
+ buf->state = send_param->state;
+ buf->seq_num = s_example_espnow_seq[buf->type]++;
+ buf->crc = 0;
+ buf->magic = send_param->magic;
+ for (i = 0; i < send_param->len - sizeof(example_espnow_data_t); i++) {
+ buf->payload[i] = (uint8_t)esp_random();
+ }
+ buf->crc = crc16_le(UINT16_MAX, (uint8_t const *)buf, send_param->len);
+}
+
+static void example_espnow_task(void *pvParameter)
+{
+ example_espnow_event_t evt;
+ uint8_t recv_state = 0;
+ uint16_t recv_seq = 0;
+ int recv_magic = 0;
+ bool is_broadcast = false;
+ int ret;
+
+ vTaskDelay(5000 / portTICK_RATE_MS);
+ ESP_LOGI(TAG, "Start sending broadcast data");
+
+ /* Start sending broadcast ESPNOW data. */
+ example_espnow_send_param_t *send_param = (example_espnow_send_param_t *)pvParameter;
+ if (esp_now_send(send_param->dest_mac, send_param->buffer, send_param->len) != ESP_OK) {
+ ESP_LOGE(TAG, "Send error");
+ example_espnow_deinit(send_param);
+ vTaskDelete(NULL);
+ }
+
+ while (xQueueReceive(example_espnow_queue, &evt, portMAX_DELAY) == pdTRUE) {
+ switch (evt.id) {
+ case EXAMPLE_ESPNOW_SEND_CB:
+ {
+ example_espnow_event_send_cb_t *send_cb = &evt.info.send_cb;
+ is_broadcast = IS_BROADCAST_ADDR(send_cb->mac_addr);
+
+ ESP_LOGD(TAG, "Send data to "MACSTR", status1: %d", MAC2STR(send_cb->mac_addr), send_cb->status);
+
+ if (is_broadcast && (send_param->broadcast == false)) {
+ break;
+ }
+
+ if (!is_broadcast) {
+ send_param->count--;
+ if (send_param->count == 0) {
+ ESP_LOGI(TAG, "Send done");
+ example_espnow_deinit(send_param);
+ vTaskDelete(NULL);
+ }
+ }
+
+ /* Delay a while before sending the next data. */
+ if (send_param->delay > 0) {
+ vTaskDelay(send_param->delay/portTICK_RATE_MS);
+ }
+
+ ESP_LOGI(TAG, "send data to "MACSTR"", MAC2STR(send_cb->mac_addr));
+
+ memcpy(send_param->dest_mac, send_cb->mac_addr, ESP_NOW_ETH_ALEN);
+ example_espnow_data_prepare(send_param);
+
+ /* Send the next data after the previous data is sent. */
+ if (esp_now_send(send_param->dest_mac, send_param->buffer, send_param->len) != ESP_OK) {
+ ESP_LOGE(TAG, "Send error");
+ example_espnow_deinit(send_param);
+ vTaskDelete(NULL);
+ }
+ break;
+ }
+ case EXAMPLE_ESPNOW_RECV_CB:
+ {
+ example_espnow_event_recv_cb_t *recv_cb = &evt.info.recv_cb;
+
+ ret = example_espnow_data_parse(recv_cb->data, recv_cb->data_len, &recv_state, &recv_seq, &recv_magic);
+ free(recv_cb->data);
+ if (ret == EXAMPLE_ESPNOW_DATA_BROADCAST) {
+ ESP_LOGI(TAG, "Receive %dth broadcast data from: "MACSTR", len: %d", recv_seq, MAC2STR(recv_cb->mac_addr), recv_cb->data_len);
+
+ /* If MAC address does not exist in peer list, add it to peer list. */
+ if (esp_now_is_peer_exist(recv_cb->mac_addr) == false) {
+ esp_now_peer_info_t *peer = malloc(sizeof(esp_now_peer_info_t));
+ if (peer == NULL) {
+ ESP_LOGE(TAG, "Malloc peer information fail");
+ example_espnow_deinit(send_param);
+ vTaskDelete(NULL);
+ }
+ memset(peer, 0, sizeof(esp_now_peer_info_t));
+ peer->channel = CONFIG_ESPNOW_CHANNEL;
+ peer->ifidx = ESPNOW_WIFI_IF;
+ peer->encrypt = true;
+ memcpy(peer->lmk, CONFIG_ESPNOW_LMK, ESP_NOW_KEY_LEN);
+ memcpy(peer->peer_addr, recv_cb->mac_addr, ESP_NOW_ETH_ALEN);
+ ESP_ERROR_CHECK( esp_now_add_peer(peer) );
+ free(peer);
+ }
+
+ /* Indicates that the device has received broadcast ESPNOW data. */
+ if (send_param->state == 0) {
+ send_param->state = 1;
+ }
+
+ /* If receive broadcast ESPNOW data which indicates that the other device has received
+ * broadcast ESPNOW data and the local magic number is bigger than that in the received
+ * broadcast ESPNOW data, stop sending broadcast ESPNOW data and start sending unicast
+ * ESPNOW data.
+ */
+ if (recv_state == 1) {
+ /* The device which has the bigger magic number sends ESPNOW data, the other one
+ * receives ESPNOW data.
+ */
+ if (send_param->unicast == false && send_param->magic >= recv_magic) {
+ ESP_LOGI(TAG, "Start sending unicast data");
+ ESP_LOGI(TAG, "send data to "MACSTR"", MAC2STR(recv_cb->mac_addr));
+
+ /* Start sending unicast ESPNOW data. */
+ memcpy(send_param->dest_mac, recv_cb->mac_addr, ESP_NOW_ETH_ALEN);
+ example_espnow_data_prepare(send_param);
+ if (esp_now_send(send_param->dest_mac, send_param->buffer, send_param->len) != ESP_OK) {
+ ESP_LOGE(TAG, "Send error");
+ example_espnow_deinit(send_param);
+ vTaskDelete(NULL);
+ }
+ else {
+ send_param->broadcast = false;
+ send_param->unicast = true;
+ }
+ }
+ }
+ }
+ else if (ret == EXAMPLE_ESPNOW_DATA_UNICAST) {
+ ESP_LOGI(TAG, "Receive %dth unicast data from: "MACSTR", len: %d", recv_seq, MAC2STR(recv_cb->mac_addr), recv_cb->data_len);
+
+ /* If receive unicast ESPNOW data, also stop sending broadcast ESPNOW data. */
+ send_param->broadcast = false;
+ }
+ else {
+ ESP_LOGI(TAG, "Receive error data from: "MACSTR"", MAC2STR(recv_cb->mac_addr));
+ }
+ break;
+ }
+ default:
+ ESP_LOGE(TAG, "Callback type error: %d", evt.id);
+ break;
+ }
+ }
+}
+
+static esp_err_t example_espnow_init(void)
+{
+ example_espnow_send_param_t *send_param;
+
+ example_espnow_queue = xQueueCreate(ESPNOW_QUEUE_SIZE, sizeof(example_espnow_event_t));
+ if (example_espnow_queue == NULL) {
+ ESP_LOGE(TAG, "Create mutex fail");
+ return ESP_FAIL;
+ }
+
+ /* Initialize ESPNOW and register sending and receiving callback function. */
+ ESP_ERROR_CHECK( esp_now_init() );
+ ESP_ERROR_CHECK( esp_now_register_send_cb(example_espnow_send_cb) );
+ ESP_ERROR_CHECK( esp_now_register_recv_cb(example_espnow_recv_cb) );
+
+ /* Set primary master key. */
+ ESP_ERROR_CHECK( esp_now_set_pmk((uint8_t *)CONFIG_ESPNOW_PMK) );
+
+ /* Add broadcast peer information to peer list. */
+ esp_now_peer_info_t *peer = malloc(sizeof(esp_now_peer_info_t));
+ if (peer == NULL) {
+ ESP_LOGE(TAG, "Malloc peer information fail");
+ vSemaphoreDelete(example_espnow_queue);
+ esp_now_deinit();
+ return ESP_FAIL;
+ }
+ memset(peer, 0, sizeof(esp_now_peer_info_t));
+ peer->channel = CONFIG_ESPNOW_CHANNEL;
+ peer->ifidx = ESPNOW_WIFI_IF;
+ peer->encrypt = false;
+ memcpy(peer->peer_addr, example_broadcast_mac, ESP_NOW_ETH_ALEN);
+ ESP_ERROR_CHECK( esp_now_add_peer(peer) );
+ free(peer);
+
+ /* Initialize sending parameters. */
+ send_param = malloc(sizeof(example_espnow_send_param_t));
+ memset(send_param, 0, sizeof(example_espnow_send_param_t));
+ if (send_param == NULL) {
+ ESP_LOGE(TAG, "Malloc send parameter fail");
+ vSemaphoreDelete(example_espnow_queue);
+ esp_now_deinit();
+ return ESP_FAIL;
+ }
+ send_param->unicast = false;
+ send_param->broadcast = true;
+ send_param->state = 0;
+ send_param->magic = esp_random();
+ send_param->count = CONFIG_ESPNOW_SEND_COUNT;
+ send_param->delay = CONFIG_ESPNOW_SEND_DELAY;
+ send_param->len = CONFIG_ESPNOW_SEND_LEN;
+ send_param->buffer = malloc(CONFIG_ESPNOW_SEND_LEN);
+ if (send_param->buffer == NULL) {
+ ESP_LOGE(TAG, "Malloc send buffer fail");
+ free(send_param);
+ vSemaphoreDelete(example_espnow_queue);
+ esp_now_deinit();
+ return ESP_FAIL;
+ }
+ memcpy(send_param->dest_mac, example_broadcast_mac, ESP_NOW_ETH_ALEN);
+ example_espnow_data_prepare(send_param);
+
+ xTaskCreate(example_espnow_task, "example_espnow_task", 2048, send_param, 4, NULL);
+
+ return ESP_OK;
+}
+
+static void example_espnow_deinit(example_espnow_send_param_t *send_param)
+{
+ free(send_param->buffer);
+ free(send_param);
+ vSemaphoreDelete(example_espnow_queue);
+ esp_now_deinit();
+}
+
+void app_main()
+{
+ // Initialize NVS
+ esp_err_t ret = nvs_flash_init();
+ if (ret == ESP_ERR_NVS_NO_FREE_PAGES) {
+ ESP_ERROR_CHECK( nvs_flash_erase() );
+ ret = nvs_flash_init();
+ }
+ ESP_ERROR_CHECK( ret );
+
+ example_wifi_init();
+ example_espnow_init();
+}
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