CR_CSR: reduce CR rom size.

28197037 · Tristan Gingold · 5feb437b · 28197037
Commit 28197037 authored Sep 18, 2017 by Tristan Gingold
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Showing with 8 additions and 4 deletions

VME_CR_CSR_Space.vhd hdl/vme64x-core/rtl/VME_CR_CSR_Space.vhd +8 -4

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--- a/hdl/vme64x-core/rtl/VME_CR_CSR_Space.vhd
+++ b/hdl/vme64x-core/rtl/VME_CR_CSR_Space.vhd
@@ -249,7 +249,7 @@ architecture rtl of VME_CR_CSR_Space is

  -- Function to encode the configuration ROM
  function f_cr_encode return t_cr_array is
-    variable cr  : t_cr_array(0 to 1023) := (others => x"00");
+    variable cr  : t_cr_array(0 to 511) := (others => x"00");
    variable crc : unsigned(7 downto 0)  := x"00";
  begin
    cr(16#001# to 16#003#)  := (x"00", x"03", x"ff");             -- Length of CR (excluding checksum)
@@ -280,14 +280,14 @@ architecture rtl of VME_CR_CSR_Space is
      cr(16#048#+i*8  to 16#04f#+i*8)  := f_cr_vec(g_AMCAP(i));   -- Function X AMCAP
      cr(16#188#+i*4  to 16#18b#+i*4)  := f_cr_vec(g_ADEM(i));    -- Function X ADEM
    end loop;
-    for i in 1 to cr'length-1 loop
+    for i in cr'range loop
      crc := crc + unsigned(cr(i));
    end loop;
    cr(16#000#)            := std_logic_vector(crc);              -- Checksum
    return cr;
  end;

-  signal s_cr_rom : t_cr_array(0 to 1023) := f_cr_encode;
+  constant s_cr_rom : t_cr_array(0 to 511) := f_cr_encode;

  ------------------------------------------------------------------------------

@@ -305,7 +305,11 @@ begin
  process (clk_i)
  begin
    if rising_edge(clk_i) then
-      s_cr_data <= s_cr_rom(to_integer(s_addr) mod 1024);
+      if s_addr(11) = '0' then
+        s_cr_data <= s_cr_rom(to_integer(s_addr(10 downto 2)));
+      else
+        s_cr_data <= x"00";
+      end if;
    end if;
  end process;