ESP-NOW speed / out of memory error
Posted: Sun Dec 08, 2019 2:28 pm
Hello,
I've not been able to find out the speed at which data can be transmitted with ESP-NOW between 2 ESP32 (close to each other), and my tests concluded for a "low" speed under 1Mbps when I would expect much more.
See simplified code below for the transmitter, I'm reading a file on and sending it over using esp_now_send (250 bytes per packet), but if I don't delay enough between each send (around 3ms) I keep getting out of memory errors (ESP_ERR_ESPNOW_NO_MEM).
Is it a limitation in the protocol, or is there something wrong I'm doing?
Maybe there is a better way to transmit the data (this is for live streaming)?
Many thanks
Ben
I've not been able to find out the speed at which data can be transmitted with ESP-NOW between 2 ESP32 (close to each other), and my tests concluded for a "low" speed under 1Mbps when I would expect much more.
See simplified code below for the transmitter, I'm reading a file on and sending it over using esp_now_send (250 bytes per packet), but if I don't delay enough between each send (around 3ms) I keep getting out of memory errors (ESP_ERR_ESPNOW_NO_MEM).
Is it a limitation in the protocol, or is there something wrong I'm doing?
Maybe there is a better way to transmit the data (this is for live streaming)?
Many thanks
Ben Code: Select all
#include <WiFi.h>
#include <esp_now.h>
#include <stdint.h>
#include <string.h>
#include <SD.h>
static uint8_t broadcast_mac[] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
File file;
typedef struct __attribute__((packed)) esp_now_msg_t
{
char data[250];
} esp_now_msg_t;
void setup() {
Serial.begin(115200);
network_setup();
SD.begin();
file = SD.open("/example.txt");
}
void loop() {
static uint32_t counter = 0;
esp_now_msg_t msg;
while (file.readBytes(msg.data, 250)) {
send_msg(&msg);
delayMicroseconds(3000);
}
file.seek(0);
}
static void send_msg(esp_now_msg_t * msg)
{
uint16_t packet_size = sizeof(esp_now_msg_t);
uint8_t msg_data[packet_size];
memcpy(&msg_data[0], msg, sizeof(esp_now_msg_t));
esp_err_t status = esp_now_send(broadcast_mac, msg_data, packet_size);
if (ESP_OK != status)
{
Serial.println("Error sending message");
handle_error(status);
}
}
static void network_setup(void)
{
//Puts ESP in STATION MODE
WiFi.mode(WIFI_STA);
WiFi.disconnect();
if (esp_now_init() != 0)
{
return;
}
esp_now_peer_info_t peer_info;
peer_info.channel = WIFI_CHANNEL;
memcpy(peer_info.peer_addr, broadcast_mac, 6);
peer_info.ifidx = ESP_IF_WIFI_STA;
peer_info.encrypt = false;
esp_err_t status = esp_now_add_peer(&peer_info);
if (ESP_OK != status)
{
Serial.println("Could not add peer");
handle_error(status);
}
}
static void handle_error(esp_err_t err)
{
switch (err)
{
case ESP_ERR_ESPNOW_NOT_INIT:
Serial.println("Not init");
break;
case ESP_ERR_ESPNOW_ARG:
Serial.println("Argument invalid");
break;
case ESP_ERR_ESPNOW_INTERNAL:
Serial.println("Internal error");
break;
case ESP_ERR_ESPNOW_NO_MEM:
Serial.println("Out of memory");
break;
case ESP_ERR_ESPNOW_NOT_FOUND:
Serial.println("Peer is not found");
break;
case ESP_ERR_ESPNOW_IF:
Serial.println("Current WiFi interface doesn't match that of peer");
break;
default:
break;
}
}