hdw-esp-now.c File Reference

Data Structures
struct	espNowPacket_t
	A packet received over ESP-NOW. More...

Macros
#define	ESPNOW_CHANNEL   11
	The WiFi channel to operate on.
#define	WIFI_PHY   WIFI_PHY_MODE_HT20
#define	WIFI_RATE   WIFI_PHY_RATE_MCS6_SGI
	The WiFi rate to run at, MCS6 with short GI, 65 Mbps for 20MHz, 135 Mbps for 40MHz.
#define	FRAMING_START_1   251
	The first random byte used as a 'start' byte for packets transmitted over UART.
#define	FRAMING_START_2   63
	The second random byte used as a 'start' byte for packets transmitted over UART.
#define	FRAMING_START_3   114
	The third random byte used as a 'start' byte for packets transmitted over UART.
#define	ESP_NOW_SERIAL_RX_BUF_SIZE   256
	The size of the UART receive buffer in bytes.
#define	ESP_NOW_SERIAL_RINGBUF_SIZE   512
	The size of the ringbuffer used to decode packets in bytes.

Enumerations
enum	decodeState_t {   EU_PARSING_FR_START_1 , EU_PARSING_FR_START_2 , EU_PARSING_FR_START_3 , EU_PARSING_MAC ,   EU_PARSING_LEN , EU_PARSING_PAYLOAD }

Functions
esp_err_t	initEspNow (hostEspNowRecvCb_t recvCb, hostEspNowSendCb_t sendCb, gpio_num_t rx, gpio_num_t tx, uart_port_t uart, wifiMode_t wifiMode)
esp_err_t	espNowUseWireless (void)
void	espNowUseSerial (bool crossoverPins)
void	checkEspNowRxQueue (void)
void	espNowSend (const char *data, uint8_t len)
void	deinitEspNow (void)

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Data Structure Documentation

espNowPacket_t

struct espNowPacket_t

Data Fields
int8_t	rssi	The received signal strength indicator for the packet.
uint8_t	mac[6]	The MAC address of the sender.
uint8_t	len	The length of the received bytes.
uint8_t	data[255]	The received bytes.

Macro Definition Documentation

ESPNOW_CHANNEL

#define ESPNOW_CHANNEL   11

The WiFi channel to operate on.

WIFI_PHY

#define WIFI_PHY   WIFI_PHY_MODE_HT20

WIFI_RATE

#define WIFI_RATE   WIFI_PHY_RATE_MCS6_SGI

The WiFi rate to run at, MCS6 with short GI, 65 Mbps for 20MHz, 135 Mbps for 40MHz.

FRAMING_START_1

#define FRAMING_START_1   251

The first random byte used as a 'start' byte for packets transmitted over UART.

FRAMING_START_2

#define FRAMING_START_2   63

The second random byte used as a 'start' byte for packets transmitted over UART.

FRAMING_START_3

#define FRAMING_START_3   114

The third random byte used as a 'start' byte for packets transmitted over UART.

ESP_NOW_SERIAL_RX_BUF_SIZE

#define ESP_NOW_SERIAL_RX_BUF_SIZE   256

The size of the UART receive buffer in bytes.

ESP_NOW_SERIAL_RINGBUF_SIZE

#define ESP_NOW_SERIAL_RINGBUF_SIZE   512

The size of the ringbuffer used to decode packets in bytes.

Enumeration Type Documentation

decodeState_t

enum decodeState_t

Enumerator
EU_PARSING_FR_START_1	Parsing state for the first framing byte.
EU_PARSING_FR_START_2	Parsing state for the second framing byte.
EU_PARSING_FR_START_3	Parsing state for the third framing byte.
EU_PARSING_MAC	Parsing state for the six MAC bytes.
EU_PARSING_LEN	Parsing state for the one length byte.
EU_PARSING_PAYLOAD	Parsing state for the payload bytes.

Function Documentation

initEspNow()

esp_err_t initEspNow	(	hostEspNowRecvCb_t	recvCb,
		hostEspNowSendCb_t	sendCb,
		gpio_num_t	rx,
		gpio_num_t	tx,
		uart_port_t	uart,
		wifiMode_t	wifiMode )

Initialize ESP-NOW and attach callback functions. This uses wifi by default, but espNowUseSerial() may be called later to communicate over the given UART instead

Parameters

recvCb	A callback to call when data is sent
sendCb	A callback to call when data is received
rx	The receive pin when using serial communication instead of wifi. Use GPIO_NUM_NC for no GPIO
tx	The transmit pin when using serial communication instead of wifi. Use GPIO_NUM_NC for no GPIO
uart	The UART to use for serial communication. Use UART_NUM_MAX for no UART
wifiMode	The WiFi mode. If ESP_NOW_IMMEDIATE, then recvCb is called directly from the interrupt. If ESP_NOW, then recvCb is called from checkEspNowRxQueue()

Returns

The esp_err_t that occurred

espNowUseWireless()

esp_err_t espNowUseWireless

(

void

)

Start wifi and use it for communication

Returns

ESP_OK or an error that occurred

espNowUseSerial()

void espNowUseSerial

(

bool

crossoverPins

)

Start the UART and use it for communication

Parameters

crossoverPins

true to crossover the rx and tx pins, false to use them as normal.

checkEspNowRxQueue()

void checkEspNowRxQueue

(

void

)

Check the ESP NOW receive queue. If there are any received packets, send them to hostEspNowRecvCb()

espNowSend()

void espNowSend	(	const char *	data,
		uint8_t	len )

This is a wrapper for esp_now_send(). It also sets the wifi power with wifi_set_user_fixed_rate()

Parameters

data	The data to broadcast using ESP NOW
len	The length of the data to broadcast

deinitEspNow()

void deinitEspNow

(

void

)

This function is called to de-initialize ESP-NOW