Espressif ESP32-S2 Programming Manual page 145

Chapter 2. API Reference
Macros
ESP_ERR_ESPNOW_BASE
ESPNOW error number base.
ESP_ERR_ESPNOW_NOT_INIT
ESPNOW is not initialized.
ESP_ERR_ESPNOW_ARG
Invalid argument
ESP_ERR_ESPNOW_NO_MEM
Out of memory
ESP_ERR_ESPNOW_FULL
ESPNOW peer list is full
ESP_ERR_ESPNOW_NOT_FOUND
ESPNOW peer is not found
ESP_ERR_ESPNOW_INTERNAL
Internal error
ESP_ERR_ESPNOW_EXIST
ESPNOW peer has existed
ESP_ERR_ESPNOW_IF
Interface error
ESP_NOW_ETH_ALEN
Length of ESPNOW peer MAC address
ESP_NOW_KEY_LEN
Length of ESPNOW peer local master key
ESP_NOW_MAX_TOTAL_PEER_NUM
Maximum number of ESPNOW total peers
ESP_NOW_MAX_ENCRYPT_PEER_NUM
Maximum number of ESPNOW encrypted peers
ESP_NOW_MAX_DATA_LEN
Maximum length of ESPNOW data which is sent very time
Type Definitions
typedef struct esp_now_peer_info
ESPNOW peer information parameters.
typedef struct esp_now_peer_num
Number of ESPNOW peers which exist currently.
typedef void (*esp_now_recv_cb_t)(const uint8_t *mac_addr, const uint8_t *data, int
Callback function of receiving ESPNOW data.
Parameters
• mac_addr: peer MAC address
• data: received data
• data_len: length of received data
typedef void (*esp_now_send_cb_t)(const uint8_t *mac_addr,
Callback function of sending ESPNOW data.
Parameters
• mac_addr: peer MAC address
• status: status of sending ESPNOW data (succeed or fail)
Espressif Systems
esp_now_peer_info_t
esp_now_peer_num_t
data_len)
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esp_now_send_status_t status)
Release v4.4