ADM-XRC SDK 2.8.1 User Guide (Linux)
© Copyright 2001-2009 Alpha Data


The ddr2sram_pinout_t datatype

The ddr2sram_pinout_t datatype is exported by the memif package, and is used to specify the physical configuration of an instance of ddr2sram_port.

It is a record type, defined as follows:

type ddr2sram_pinout_t is
record
    family        : family_t;
    has_c         : boolean;
    has_cq        : boolean;
    capture_180   : boolean;
end record;

This datatype can normally treated as an abstract datatype, since the user application need typically only use one of the predefined constants of type ddr2sram_pinout_t. However, should it be necessary to create a new value, the members are defined as follows:

Member Type Function
family family_t Specifies the FPGA family that the memory port targets.
has_c boolean If true, the rc bus of the memory port includes the C / C# pins.
has_cq boolean If true, the rc bus of the memory port includes the CQ / CQ# pins.
capture_180 boolean If true, the memory port uses the clk180 clock phase to capture DQ for reads. If false, the memory port uses the clk90.

The value of ddr2sram_pinout_t passed in the pinout parameter of a ddr2sram_port determines the proper value to pass for the rc_width parameter. The relevant formula is:

A = (rd_width / 8)
B = 2 if has_c else 0
C = 2 if has_cq else 0

rc_width = A + B + C + 5

 


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