how to load coefficientsin an FIR filter

Hi all.

I am doing my final year project on a stratix II FPGA Board.

When I use actual coefficients with coefficients stored in logic cells, the filter works well but when I used M512 and bit width only with coefficient reload activated I can't see any results on on the spectrum analyser.

1. Can someone please tell me how this works when M512 instead of Logic cells are used?

2. Is it possible to send the coefficients from PC through RS232 uart ->sdram->then to coef_in port?

I appreciate your replies