burst read and write DDR2 using altmemphy

Device: EP4CE22F17C8

Memeory: Micron MT47H64M8CB-3

IP: altmemphy DDR2

local max Burst count = 64

Operation: 1 time burst write data -> 1 time burst read data

issue: when set local size = 2, it works fine.

when set local size = 16, we can not get data read out. (local_rdata_valid = low)

Please see attachment for project code.