# Research on an Intelligent Test Method for Interconnect Resources in an FPGA
## 6 Discussion and Conclusions  
The automated modeling and intelligent wiring methods proposed in this article were successfully applied to the connection resource test development of AMD Xilinx's XC7K325T FPGA, achieving the automatic generation of interconnect resource tests. Table 2 compares the modeling method of the interconnecting metal segment lines as a point on a mathematical graph with the traditional modeling method. The original point information is successfully compressed by nearly half, as shown in Equation (6), where 363 represents the number of points to be processed for a single switch matrix in traditional modeling, and 202 is the number of points to be processed for a single switch matrix after modeling optimization. \(N\) represents the total number of switch matrices inside the FPGA. Compared with the traditional modeling method, this method compresses the modeling space and reduces the search points when searching the routing path. Consequently, this method is faster and does not require a separate calculation of the next traversal coordinates of the current traversal. \[\text{Compression ratio}=\frac{(363-202)*N}{363*N}=44.35\% \tag{6}\]  
Compared with the theory used in [17], the work reported in this paper adopts an improved depth optimization algorithm for searching the wiring path that is more intelligent and automatic. It does not need to observe the direction of the path in each switch matrix in advance or plan the wiring according to the usual laws. Table 3 shows the comparison results for the wiring of the sextuple line using the theory used in [9; 18]. Due to the vast and complex nature of FPGA interconnect resources, multiple path searches and configurations are required to achieve high coverage. The \"Times\" column in Table 3 represents the number of configurations, while the \"Pre-planned\" column indicates whether advance planning is needed before searching the path, including finding wiring patterns or planning the direction of wiring according to a predetermined plan. There are various types of linear wires between the interconnection relationships of the six-fold line. Although the coverage rate of the running results can reach 100%, there are too many operations. In summary, the improved depth-first algorithm discussed in this paper achieves a high coverage without requiring advanced observation and planning, making it suitable for FPGA interconnect resource testing. \begin{table}
\begin{tabular}{c c c} \hline \hline  & **Before Optimization** & **After Optimization** \\ \hline Single switch matrix math & & \\ graph scale (points) & 363 & 202 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Modeling optimization comparison. Figure 9: DUT test board. **Author Contributions:** [PERSON] proposed the research topic, designed the research plan and specific implementation process, participated in the writing of the paper, and proposed the revision plan; [PERSON] participated in the discussion and specific implementation of the research plan and the writing of the papers and participated in revisions; [PERSON] is an experienced FPGA test engineer who guided specific cabling operations and ATE machine operations; and [PERSON] provided the data and technical support and guidance for some modules during the implementation of the project and proposed revisions to the paper. All authors have read and agreed to the published version of the manuscript. **Funding:** This research received no external funding. **Institutional Review Board Statement:** Not applicable. **Informed Consent Statement:** Not applicable. **Data Availability Statement:** The code is available at [[https://github.com/wenjingqi7/resources](https://github.com/wenjingqi7/resources)]([https://github.com/wenjingqi7/resources](https://github.com/wenjingqi7/resources)) (github.com) (accessed on 1 June 2023). **Acknowledgments:** We would like to thank [PERSON] and [PERSON] for their academic guidance and valuable comments on the paper.