Implementing the TAP controller within the SoC, interfacing with the JTAG chip in the JTAG hardware box to receive and process JTAG sequences. Its main structure is as follows:As can be seen, there is a state machine, an Instruction Register (IR), several Data Registers (DR), a Bypass Register, etc.The state machine is controlled by TMS, … Read more
State machines are ubiquitous in embedded software, and you might say, what is so difficult about state machines? Aren’t they just switches? Switch is merely the most basic point; there are many more operations regarding state machines that you may not have encountered. Below, I will share several implementation methods. 1. Basic Terminology of State … Read more
Yesterday, a colleague called me in a panic, saying: “Wen, help! My PLC-based smart home system is completely down, and the owner is coming for acceptance in half an hour!” Hearing this familiar “fire-fighting” scenario made me smile. Ten years ago, I was in the same boat, where a small issue could drive me crazy … Read more
Word count: 1092, reading time approximately 6 minutes Continuing from the last session, today we will implement the functionality of UART, primarily using the hardware description language Verilog. The interface design is actually quite simple. If we distill its essence, it can be divided into three main parts: data acquisition, state machine, and interface timing. … Read more
Yesterday, I received a request for help from a colleague who said that the intelligent building automation system he was responsible for was always “misbehaving”—the corridor lights would turn on and off unpredictably, and the conference room air conditioning was fluctuating between hot and cold. I immediately recognized that this was the fault of the … Read more
Over the years, I have seen too many on-site programs, especially in the area of PLC sequential control, where the choice of variable types is poor, leading to numerous pitfalls. A few days ago, I went to a food factory to troubleshoot, and the program almost drove me crazy. They used a bunch of BOOL … Read more
Hello everyone! Today, I want to share not just dry coding rules, but 6 practical skills that can help your microcontroller projects succeed and double your code efficiency. These experiences come from my years of lessons learned from mistakes, specifically addressing the “program runs but is not user-friendly” issues! 1. Project Planning: Draw the Map … Read more
Input Events to State Machine #include "stdio.h" #define EXECUTE_VOID(func) {if((func)!=NULL) (func());} typedef void (*select_machine_t)(void); typedef enum _event_index{ event_index_1 = 0, event_index_2, event_index_3, event_index_end} event_index_e; typedef enum _status_index{ status_index_1 = 0, status_index_2, status_index_end} status_index_e; void machine_1(void);void machine_2(void);void machine_3(void);void machine_4(void); select_machine_t select_machine[event_index_end][status_index_end] = { {machine_1, machine_2}, {NULL, machine_3}, {machine_4, NULL}}; void machine_1(void){ printf("machine_1\r\n");} void machine_2(void){ printf("machine_2\r\n");} void … Read more
I am Lao Wen, an embedded engineer who loves learning. Follow me, and let's become better together! The state machine pattern is a behavioral pattern that effectively implements state transitions through polymorphism. Unfortunately, in embedded environments, we often have to write pure C code, and we also need to consider reentrancy and multitasking requests, which … Read more
In communication design, considering the flexibility of the protocol often leads to designing protocols as “variable length”. An example is shown in the figure below: the communication protocol frame of the Ruimi LoRa terminal. If a system receives the above “variable length” protocol frame, there will be a challenge—how to efficiently receive and parse it. … Read more