To add more functionality to the PCI device driver we wrote, we simulated a test PCIe device on QEMU, allowing us to implement features we wanted, such as DMA and interrupts. For the specific implementation of this PCIe test device, please refer to How to Implement a PCIe Device in QEMU. The Vendor ID and … Read more
1. Overview of CPU I/O Capabilities The CPU not only has computational capabilities but also needs to exchange data with external devices, a capability known as I/O (Input/Output) capability. Typical I/O operations in a computer system include: Keyboard input Display output Disk read/write Network communication, etc. 2. Two Core Issues in Peripheral Interaction 1. Peripheral … Read more
Concept of DMA DMA (Direct Memory Access) allows data transfer without direct control from the CPU. It creates a direct pathway for data transfer between RAM and I/O devices, significantly improving CPU efficiency. There are several methods for UART data reception: the interrupt mode of UART isthe most commonly used data transmission method in microcontrollers, … Read more
The SPI (Serial Peripheral Interface) is one of the most widely used synchronous serial communication protocols in embedded systems, playing a crucial role in STM32 development. Compared to I2C and UART, SPI is particularly suitable for high-speed data acquisition, memory expansion, and display driving due to its full-duplex communication, high transmission rates, and hardware slave … Read more
Previous articles mainly focused on the Processing System (PS) of the Zynq SoC, including: Using MIO and EMIO The interrupt structure of Zynq SoC Zynq private timers and watchdogs The triple timer counter (TTC) of Zynq SoC However, from a design perspective, the truly exciting aspect of the Zynq SoC is creating applications that utilize … Read more
Click 👆👆👆 the blue text Follow “Passion Embedded” In embedded development, especially in the development of microcontrollers like STM32, the <span>volatile</span> keyword is a very important concept. 1. Concept of the volatile Keyword <span>volatile</span> is a type modifier in C/C++ that tells the compiler: The variable may be modified unexpectedly (e.g., by hardware, interrupts, or … Read more
Click 👆👆👆 the blue text Follow “Passion Embedded” In embedded development, especially in the development of microcontrollers like STM32, the <span>volatile</span> keyword is a very important concept. 1. Concept of the volatile Keyword <span>volatile</span> is a type modifier in C/C++ that tells the compiler: The variable may be modified unexpectedly (e.g., by hardware, interrupts, or … Read more
In embedded system development, driver design is a key factor affecting system performance, energy efficiency, and maintainability. Below is an in-depth analysis of three mainstream driver design techniques along with practical recommendations: 1. Polling Driver Technical Features: Blocking Design: The main program cannot perform other tasks while waiting for peripheral responses. Simple Implementation: Only requires … Read more
In embedded system development, efficient and reliable communication with peripherals is crucial. The OneWire protocol, with its simple single-wire interface and cost-effectiveness, is widely used for connecting devices such as temperature sensors and iButtons. However, traditional OneWire libraries are often too bulky and resource-intensive. Today, we will delve into a lightweight, high-performance OneWire protocol library—LwOW, … Read more
CPU: STM32F429IGT6 For other STM32 chips or other ARM Cortex-M chips, the solution is generally the same. It is recommended to read this article in full before debugging the issues you encounter. 1. Basic Knowledge In ARM Cortex-M series processors, there are several system exceptions dedicated to fault handling. The faults in CM3 can be … Read more