Open Source HDLC(High Level Data Link Layer Control) and fault tolerant frame syncronization IPs using VHDL. Frame syncronization IP can also detect spectrum inversion.
Testbenches could have been much readable. But I didn't know about it at that time.
Written by Ahmet Kaan Büyükkaya
https://www.linkedin.com/in/ahmet-kaan-b%C3%BCy%C3%BCkkaya-516684145/