Question: JTAG has 5 ports, why is Trst an optional reset port? Question: If JTAG only retains 4 ports, how do we reset without Trst? Answer: The first question is simple; Trst can be replaced with Tms. What about the second question? Feel free to discuss in our knowledge community. Question: After adding mbist and … Read more
Instruction Register (IR) 指令寄存器 The purpose of the Instruction Register (IR) is to shift in instructions via the TDI signal. Additionally, the instruction register can hold the current instruction until the new instruction is completely shifted in. Generally, an IR consists of two registers as shown in Figure 1. The Hold register stores the previous … Read more
Boundary Scan Technology can not only test the logical functions of chips or PCBs but also check for faults in the connections between IC (Integrated Circuit) and PCB (Printed Circuit Board). Therefore, it has become mainstream in the design for testability of digital systems. The IEEE established the relevant standard, IEEE 1149.1, in 1990, which … Read more
01 Introduction to JTAG JTAG (Joint Test Action Group) is an interface established by a group called the JTAG group, founded in 1985. In 1990, IEEE deemed everything appropriate and released IEEE Standard 1149.1-1990, named the Standard Test Access Port and Boundary-Scan Architecture, which is the renowned JTAG. Do you know the three main functions … Read more
After familiarizing ourselves with the JTAG architecture through a series of previous articles, let’s take a complete example to understand how the TAP used for Debug access works. Assuming a debugging scenario where we need JTAG to access and modify a 3-bit wide control signal due to debugging requirements. In normal functional mode, the value … Read more
1Introduction Online debugging (OCD, On-Chip Debugging) interfaces provide chip-level control over target devices, serving as a primary means for engineers, researchers, and hackers to extract firmware code or data, modify memory contents, or change device operations. If you are familiar with hardware circuits or embedded systems, you certainly know that JTAG (Joint Test Action Group) … Read more
As an embedded engineer, you should know about download debuggers, but do you really understand the meanings and differences between the SWD and JTAG interfaces? 1 What is a Download Debugger In simple terms, a download debugger is a device that converts commands sent from a PC (for example, via USB protocol) into a language … Read more
If you don’t want to miss my updates, remember to check the public account in the upper right corner and set it as a star, giving me a star in return. Based on the Cortex-M core, the mainstream download interfaces are JTAG and SWD. Differences Between SWD and JTAG Pins: JTAG: TDI: Test Data In. … Read more
1 Reasons Driving Change in FPGA Debugging Technology The reprogramming capability of FPGAs is a key advantage in the functional debugging of hardware designs. In the early days of using CPLDs and FPGAs, when a design was found to be malfunctioning, engineers would use the “debug hook” method. They would route the internal signals of … Read more
This is a multi-functional online writer board that integrates EMMC flying wire, UART serial port, and JTAG functionality for variable frequency air conditioners, compatible with the RT809H programmer. EMMC Flying Wire Interface: It can directly provide the required 3.3V and 1.8V voltage to the motherboard, making it convenient to power the EMMC during board repairs, … Read more