Simple MAX 10 project with DDR3 UniPHY using HDL only

I want to implement a simple hdl design for the Arrow DECA. Most examples make use of other IP's like the Nios II Processor to control the DDR3 SDRAM. But I want to build my IP Variation and control it using VHDL or Verilog HDL only, thus, using the MegaWizard Plug-In, I configured MY_DDR3.v bassed on an example by the manufacturer (Terasic).

In my code (attached) I try to read and write simple data using simple buttons, a dip switch and a lcd to display my results. What I don't understand is why the wire "avl_ready", just won't turn on again after I do my write or read request.

Additionally, what I don't fully comprehend is the function avl_burstbegin, avl_be and avl_size. I think the "External Memory Interface Handbook Volume 3" is too advanced for me.

Thank you for your attention, I would like to hear your advice and I hope the best. Greetings.