PoC.mem.sdram.ctrl_phy_de0

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Physical layer used by module sdram_ctrl_de0.

Instantiates input and output buffer components and adjusts the timing for the Altera DE0 board.

Clock and Reset Signals

Port Description
clk Base clock for command and write data path.
rst Reset for clk.

Command signals and write data are sampled with clk. Read data is also aligned with clk.

Write and read enable (wren_nxt, rden_nxt) must be hold for:

  • 1 clock cycle if BL = 1,
  • 2 clock cycles if BL = 2, or
  • 4 clock cycles if BL = 4, or
  • 8 clock cycles if BL = 8.

They must be first asserted with the read and write command. Proper delay is included in this unit.

The first word to write must be asserted with the write command. Proper delay is included in this unit.

Synchronous resets are used. Reset must be hold for at least two cycles.

Entity Declaration:

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entity sdram_ctrl_phy_de0 is
  generic (
    CL : positive);                     -- CAS latency
  port (
    clk     : in std_logic;
    clkout  : in std_logic;
    rst     : in std_logic;
    
    sd_cke_nxt : in std_logic;
    sd_cs_nxt  : in std_logic;
    sd_ras_nxt : in std_logic;
    sd_cas_nxt : in std_logic;
    sd_we_nxt  : in std_logic;
    sd_ba_nxt  : in std_logic_vector(1 downto 0);
    sd_a_nxt   : in std_logic_vector(11 downto 0);
    
    wren_nxt  : in std_logic;
    wdata_nxt : in std_logic_vector(15 downto 0);
    
    rden_nxt : in  std_logic;
    rdata    : out std_logic_vector(15 downto 0);
    rstb     : out std_logic;
    
    sd_ck   : out   std_logic;
    sd_cke  : out   std_logic;
    sd_cs   : out   std_logic;
    sd_ras  : out   std_logic;
    sd_cas  : out   std_logic;
    sd_we   : out   std_logic;
    sd_ba   : out   std_logic_vector(1 downto 0);
    sd_a    : out   std_logic_vector(11 downto 0);
    sd_dq   : inout std_logic_vector(15 downto 0));
    
end sdram_ctrl_phy_de0;