The HTTP protocol stands for Hyper Text Transfer Protocol, which is used to transfer hypertext from World Wide Web (WWW) servers to local browsers. It operates based on TCP/IP communication, thus functioning on a client-server model. It is an application layer protocol that can be used to transfer various resources from the server, such as … Read more
1. Is the on-chip RAM exhausted? Two different STM32 users reported similar issues. While compiling example projects from the STM32F7Cube library, they encountered a puzzling message indicating that the on-chip RAM was nearly depleted. Given their understanding of the basic functionalities of the project, this shouldn’t have been the case, and they wanted to know … Read more
Those involved in embedded development know that the network protocol stack is the “skeleton” for device networking. However, the “small body” of embedded devices (with a few KB of memory and tens of MHz of clock speed) cannot handle the protocol stacks used on PCs, which is why lightweight embedded network protocol stacks have become … Read more
“ This article focuses on the Wi-Fi architecture and TCP/IP protocol implementation of the ESP32-S3. It analyzes the core modules integrated into its 40nm chip, including the RF front end and baseband, details the STA/AP working modes, dissects the STA connection process and data path, and compares the OSI and TCP/IP protocol stack implementations.” 01 … Read more
“This article introduces the Wi-Fi UDP communication of the ESP32-S3. It is based on a dual-core processor, supports relevant protocols, and implements UDP transmission through the lwIP protocol stack. The article explains the working principle and process, provides program design code, and demonstrates test results, highlighting its application in scenarios such as the Internet of … Read more
This is a project experience shared by a colleague of mine. They developed an industrial gateway based on STM32F767 for a factory, which is used for: Collecting data from multiple Modbus/485 sensors Uploading data to the dispatch server via TCP/UDP protocol Supporting up to 32 devices connected simultaneously (LwIP + RAW API) Initial small-scale tests … Read more
Click the blue text Follow us 1. Overview Ethernet refers to the baseband local area network specification created by Xerox and jointly developed by Xerox, Intel, and DEC. Ethernet uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) technology and operates at a rate of 10M/S over various types of cables. Ethernet is similar to … Read more
MQTT, as a lightweight publish/subscribe messaging protocol, provides real-time and reliable messaging services for resource-constrained IoT devices in low bandwidth, high latency, or unstable network environments. lwIP, as a similarly lightweight TCP/IP protocol implementation, minimizes the use of hardware resources, especially memory, while providing complete TCP/IP functionality, making lwIP very suitable for small embedded systems. … Read more
5. LwIP Memory Management 1. What is Memory Management? (1) Memory management refers to the techniques used for the allocation and utilization of computer memory resources during software execution. Its main purpose is to efficiently and quickly allocate memory and to release and reclaim memory resources at appropriate times (similar to the malloc and free … Read more
LwIP protocol stack supports various network interfaces (network cards). Since network cards interact directly with the hardware platform, the handling differs based on the hardware. How does LwIP accommodate these different network cards? LwIP provides a unified interface, while the underlying functions need to be implemented by the user, such as initializing the network card, … Read more