EN.md

@@ -14,6 +14,13 @@
 # Homework
 ## [1.Designing a traffic light controller using verilog](https://git.tongji.edu.cn/groups/intelli_chip_and_system_design_course/-/wikis/Homework1.Designing-a-traffic-light-controller-using-verilog)
 
+
+---
+# Reference
+
+[Sipeed Tang Primer 20K reference](https://wiki.sipeed.com/hardware/en/tang/tang-primer-20k/primer-20k.html)
+
+[Sipeed Tang Primer 20K examples on Github](https://github.com/sipeed/TangPrimer-20K-example)
 ---
 # Tips/FAQs