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Cyclone III DDR2 HPCII burst problem

Honored Contributor II

Hi all, 


Currently I have some problem of utilizing HPCII burst. My configurations are listed below: 

PLL reference clock frequency: 75MHz 

Memory clock frequency: 150MHz 

Controller data rate: Half 

Local interface clock frequency: 75MHz 

Local interface width: 128 bits 

Total memory interface DQ width: 32 bits 

Memory burst length: 8 beats 

Controller architecture: HPCII 

Local-to-Memory Address Mapping: CHIP-ROW-BANK-COL 

Local Maximum Burst Count: 16 


I wrote the Avalon-MM master local side control logic by myself, and it has output of local_burstcount[4:0], which should match "Local Maximum Burst Count: 16" on HPCII side. When I connected my Avalon-MM local side master with HPCII in SOPC builder and generated Verilog simulation model, I observed that in the arbitrator generated by SOPC builder, it always set the burst count to 1 instead of connecting local_size[4:0] port of HPCII to local_burstcount[4:0] port in my Avalon-MM master: 


//burstcount mux, which is an e_mux 

assign altmemddr_0_s1_burstcount = 1; 


Due to the above assignment, my HPCII local_size[4:0] is always 1 no matter what value is assigned on my Avalon-MM master local_burstcount[4:0] output. Therefore, there's no local burst on HPCII. How can I fix this problem and enable a local burst of value greater than 1? 


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2 Replies
Honored Contributor II

Did anybody encounter this issue?

Honored Contributor II

Are you sure your Avalon-MM master interface works at the same frequency as your memory?