under construction
ESP - wifi Communication ESP-NOW
The cansat kit use the IOT protocol stack ESP_NOW
So the words on this page is targeted ESP-NOW rather than the cansat kit.
It has many facilities and it is out of scope to discuss it here.
So just a few words
Packet capacity and communication issues
The cansat kit's communication is based on a send and receive packet system.
The TX(transmit) function used i esp_now_send at the lowest user layer.
esp_now_send
It is important to mention that esp_now_send can only handle user data packages up to 250 Byte.
A call back facility is used to receive data:
From the link above:
If there is a lot of ESP-NOW data to send, call esp_now_send() to send less than or equal to 250 bytes of data once a time. Note that too short interval between sending two ESP-NOW data may lead to disorder of sending callback function. So, it is recommended that sending the next ESP-NOW data after the sending callback function of the previous sending has returned. The sending callback function runs from a high-priority Wi-Fi task. So, do not do lengthy operations in the callback function. Instead, post the necessary data to a queue and handle it from a lower priority task.
The expressif pages contains lot of valid informateion
FYI
The source for esp_now_send and the whole wifi stack is NOT open source and is not available
Happy hacking :-)
THE BEER-WARE LICENSE (Revision v 42)
jensd@jensd.dk wrote this file.
As long as you retain this notice you can do whatever you want with this stuff on these pages.
If we meet some day, and you think this stuff is worth it, you can buy me a beer in return :-)
(C) Jens Dalsgaard Nielsen
credit for license this goes to phk@FreeBSD.ORG
As long as you retain this notice you can do whatever you want with this stuff on these pages.
If we meet some day, and you think this stuff is worth it, you can buy me a beer in return :-)
(C) Jens Dalsgaard Nielsen
credit for license this goes to phk@FreeBSD.ORG