Cyclone® V Hard Processor System Technical Reference Manual
29.1.3. FPGA-to-HPS SDRAM Interface
The FPGA-to-HPS SDRAM interface is a direct connection between the FPGA fabric and the HPS SDRAM controller. This interface is highly configurable, allowing a mix between number of ports and port width. The interface supports both AXI* -3 and Avalon-MM protocols.
|   Interface Name  |  
         Description  |  
         Associated Clock Interface  |  
      
|---|---|---|
|   f2h_sdram0_data  |  
         SDRAM AXI* or Avalon-MM port 0  |  
        f2h_sdram0_clock  |  
      
|   f2h_sdram1_data  |  
         SDRAM AXI* or Avalon-MM port 1  |  
        f2h_sdram1_clock  |  
      
|   f2h_sdram2_data  |  
         SDRAM AXI* or Avalon-MM port 2  |  
        f2h_sdram2_clock  |  
      
|   f2h_sdram3_data  |  
         SDRAM AXI* or Avalon-MM port 3  |  
        f2h_sdram3_clock  |  
      
|   f2h_sdram4_data  |  
         SDRAM AXI* or Avalon-MM port 4  |  
        f2h_sdram4_clock  |  
      
|   f2h_sdram5_data  |  
         SDRAM AXI* or Avalon-MM port 5  |  
        f2h_sdram5_clock  |  
      
The FPGA-to-HPS SDRAM interface is a configurable interface to the multi-port SDRAM controller.
The total data width of all interfaces is limited to a maximum of 256 bits in the read direction and 256 bits in the write direction. The interface is implemented as four 64-bit read ports and four 64-bit write ports. As a result, the minimum data width used by the interface is 64 bits, regardless of the number or type of interfaces.
You can configure this interface the following ways:
- AXI* -3 or Avalon-MM protocol
 - Number of interfaces
 - Data width of interfaces
 
The FPGA-to-HPS SDRAM interface supports six command ports, allowing up to six Avalon-MM interfaces or three bidirectional AXI* interfaces.
Each command port is available either to implement a read or write command port for AXI* , or to form part of an Avalon-MM interface.
You can use a mix of Avalon-MM and AXI* interfaces, limited by the number of command/data ports available. Some AXI* features are not present in Avalon-MM interfaces.
This interface has an address width of 32 bits. To access existing Avalon-MM/ AXI* masters, you can use the Address Span Extender.