In the increasingly complex aviation electronic systems, FPGA (Field Programmable Gate Array) has become a key technology in aviation electronic system design due to its high flexibility, parallel processing capability, and reconfigurability. However, to ensure the stable and reliable operation of avionics FPGA in actual flight environments, a precise and efficient physical testing system is indispensable. The avionics FPGA physical testing system covers multiple aspects from hardware architecture construction to comprehensive functional verification, and is an important barrier to ensure the quality of avionics equipment.
1、 Overview of System Architecture
The avionics FPGA physical testing system adopts a modular design concept, mainly consisting of a main control module, signal excitation module, data acquisition module, power management module, and communication interface module. The main control module, as the "brain" of the entire system, is usually served by high-performance processors or controllers, responsible for coordinating the entire testing process, receiving user input testing instructions, and analyzing and processing test data. The signal excitation module is used to generate various types of excitation signals, simulate different signals that FPGA may receive in actual flight, such as analog signals, digital signals, high-speed serial signals, etc., to verify the FPGA's response capability under different operating conditions. The data acquisition module is responsible for real-time acquisition of signal data output by FPGA, converting it into digital quantity and transmitting it to the main control module for analysis. The power management module provides stable and reliable power supply for various parts of the system, and has overvoltage and overcurrent protection functions to ensure that the testing system operates within a safe voltage and current range. The communication interface module enables data exchange between the testing system and external devices (such as computers, other testing instruments, etc.), making it convenient for users to set testing parameters, view test results, and store data.
2、 Core testing function
（1） Functional testing
Functional testing is the fundamental task of avionics FPGA physical testing system. By inputting specific test vectors into the FPGA, check if its output meets the design expectations. For example, for FPGAs that implement data processing functions in avionics systems, the testing system will input data in different formats and contents to verify whether the FPGA can correctly perform operations such as data parsing, computation, and forwarding. In addition, comprehensive testing will be conducted on the logic functions inside the FPGA, including functional verification of modules such as state machines, counters, and memory, to ensure that the FPGA can operate stably under various logic state transitions.
（2） Performance testing
Performance testing aims to evaluate the performance of avionics FPGA in actual operation. Among them, timing testing is an important part of performance testing, which determines whether the FPGA meets the timing specifications required by the design by measuring parameters such as the establishment time, holding time, and clock jitter of the internal signals of the FPGA. If there are timing issues with FPGA, it may lead to serious consequences such as data transmission errors and logic function failures. In addition, throughput testing is also a key component of performance testing, which measures the amount of data that FPGA can process per unit time to determine whether FPGA can meet the data processing speed requirements of avionics systems.
（3） Reliability testing
Reliability testing is an important means to ensure the stable operation of avionics FPGA in complex flight environments. This test mainly includes temperature testing, humidity testing, vibration testing, and electromagnetic compatibility testing. In temperature testing, the testing system is placed in different temperature environments (such as high temperature, low temperature, temperature cycling) to observe the working status of the FPGA and evaluate its reliability under extreme temperature conditions. The humidity test simulates a high humidity environment to detect whether the FPGA will experience performance degradation or malfunction due to moisture. Vibration testing simulates the vibration environment during aircraft flight, checking whether the pins, solder joints, etc. of FPGA will loosen or fall off due to vibration. Electromagnetic compatibility testing is used to evaluate the anti-interference ability of FPGA in complex electromagnetic environments and its own electromagnetic radiation level, ensuring that it will not interfere with other avionics equipment and can also resist external electromagnetic interference.
3、 Key points of hardware design
（1） FPGA chip selection
The selection of FPGA chips directly affects the performance and functionality of the testing system. In the field of avionics, it is necessary to choose FPGA chips with high reliability, low power consumption, large capacity logic resources, and rich I/O interfaces. For example, some high-end FPGA chips have radiation resistance and can effectively cope with radiation interference in aviation environments, making them suitable for use in key parts of avionics systems. At the same time, according to specific testing requirements, the processing speed, storage capacity, and other parameters of FPGA chips should be considered to ensure that they can meet the requirements of the testing system for signal processing and data storage.
（2） Design of High Speed Signal Processing Circuit
There are a large number of high-speed signals in the avionics system, such as high-speed serial data buses, high-frequency clock signals, etc. Therefore, the hardware design of the testing system needs to focus on high-speed signal processing circuits. In the process of high-speed signal transmission, there will be problems such as signal attenuation, reflection, and crosstalk, which require the use of appropriate transmission line design and impedance matching technology. For example, high-speed signal transmission can be achieved using microstrip or strip lines, and low loss transmission and good signal integrity can be achieved through reasonable wiring layout and termination resistance design. In addition, it is necessary to perform clock recovery and data synchronization processing on high-speed signals to ensure that the FPGA can accurately receive and process these high-speed signals.
（3） Power supply design
A stable power supply is the foundation for the normal operation of avionics FPGA physical testing systems. Due to the high stability and noise requirements of FPGA chips for power supply, multi-stage filtering and voltage stabilization measures need to be adopted in power supply design. Firstly, high-frequency noise and interference signals in the power grid are removed through a power filter; Then, a linear stabilized power supply or a switching stabilized power supply is used to stabilize the input power supply, ensuring the accuracy and stability of the output voltage. At the same time, in order to reduce the impact of power noise on FPGA, decoupling capacitors need to be added at the power pins of FPGA chips to suppress the conduction and radiation of power noise.
4、 Software Design and Testing Process
（1） Software Design
The software part of the avionics FPGA physical testing system mainly includes testing control software and data analysis software. The test control software is responsible for interacting with the hardware to send test instructions, collect test data, and control the testing process. It usually adopts a graphical interface design, which facilitates users to set testing parameters and monitor the testing process. Data analysis software conducts in-depth analysis and processing of collected test data, extracts useful information through various algorithms and tools, and generates test reports. For example, using statistical analysis methods to process test data and determine whether the performance indicators of FPGA meet the requirements; Visualize the signal waveform through waveform analysis tools to help users intuitively understand the working status of FPGA.
（2） Testing process
The testing process of avionics FPGA physical testing system generally includes three stages: test preparation, test execution, and test result analysis. In the testing preparation phase, it is necessary to connect the hardware devices of the testing system, set the testing parameters such as the type, frequency, amplitude, etc. of the excitation signal, and load the corresponding testing program. During the testing execution phase, the main control module sends excitation signals to the FPGA according to the predetermined testing process. The data acquisition module collects real-time output data from the FPGA and transmits it to the data analysis software for processing. Finally, during the test result analysis phase, the data analysis software conducts a comprehensive analysis of the test data to determine whether the FPGA has passed the test and generates a detailed test report. If there are issues with the FPGA, the test report will clearly indicate the type and location of the problem for developers to debug and improve.
The avionics FPGA physical testing system provides strong support for the quality assurance of avionics FPGA through scientific and reasonable architecture design, comprehensive testing functions, and precise hardware and software design. With the continuous development of avionics technology, the performance and reliability requirements for avionics FPGAs are also increasing. The physical testing system for avionics FPGAs will also be continuously upgraded and improved to adapt to new technological challenges and demands.
The above article introduces the avionics FPGA physical testing system from multiple aspects. If you feel that certain parts require additional details or specific directions for modification, please feel free to let me know at any time.