Cyclone® V Hard Processor System Technical Reference Manual

ID 683126
Date 8/28/2023
Public
Document Table of Contents

10.3.9.4. The SDRAM Region

The SDRAM region starts at address 0x100000 (1 MB). The top of the region is determined by the L2 cache filter.

The L2 cache contains a filtering mechanism that routes accesses to the SDRAM and system interconnect. The filter defines a filter range with start and end addresses. Any access within this filter range is routed to the SDRAM subsystem. Accesses outside of this filter range are routed to the system interconnect.

The start and end addresses are specified in the following register fields:

  • reg12_addr_filtering_start.address_filtering_start
  • reg12_address_filtering_end.address_filtering_end

To remap the lower 1MB of SDRAM into the boot region, set the filter start address to 0x0 to ensure accesses between 0x0 and 0xFFFFF are routed to the SDRAM. Independently, you can set the filter end address in 1 MB increments above 0xC0000000 to extend the upper bounds of the SDRAM region. However, you achieve this extended range at the expense of the FPGA peripheral address span. Depending on the address filter settings in the L2 cache, the top of the SDRAM region can range from 0xBFFFFFFF to 0xFBFFFFFF.