Hi @Nagendra,

These type of questions are outside of the scope of the PYNQ support.

I suggest you familiarize yourself with AXI4-Stream and how the DMA works. As you will learn from the link below, TLAST signals the last byte of the stream so it cannot be asserted all the time.

A good starting point here How-AXI4-Stream-Works

You can also review Cathal’s tutorial Tutorial: using a HLS stream IP with DMA (Part 1: HLS design), you can add ILA in that design so you can learn how it is working.