📝 This post was initially released on the HLS Works Blog in 2020. The post was moved to this website after HLS Works closed in Sep 2021. The AXI Master interface in HLS (The Basics) The AXI4 master is a powerfull interface that supports many features, but probably the most remarkable feature is support for burst transactions (Covered in detail in this post). An AXI Master (AXIM) interface is commonly used to access the DDR memory, though it can also be used to access other cores, such as BRAM or URAM.