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vhdl/projects/mips_sys/src/sdram_config.vhd
T
jens b8a69d571a - made time specs in SDRAM_config independent of SDRAM clock
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git-svn-id: http://moon:8086/svn/vhdl/trunk@718 cc03376c-175c-47c8-b038-4cd826a8556b
2010-02-07 12:54:24 +00:00

75 lines
3.2 KiB
VHDL

-------------------------------------------------------------------------
-- Project: SDRAM controller
-- This file: User SDRAM component adjustments
--
-- Copyright (C) 2007 J. Ahrensfeld
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
--
-- For questions and ideas, please contact the author at jens@jayfield.org
--
--------------------------------------------------------------------------
library IEEE;
USE IEEE.STD_LOGIC_1164.ALL;
USE IEEE.NUMERIC_STD.ALL;
package sdram_config is
constant DDR_DATA_WIDTH : positive := 32; -- External DDR-SDRAM Module data bus width
constant DDR_ADDR_WIDTH : positive := 13; -- number of address lines to DDR-SDRAM Device/Module
constant DDR_BANK_WIDTH : positive := 2; -- Number of BANK address lines of external DDR-SDRAM
constant DDR_ROW_ADDR_WIDTH : positive := 13; --
constant DDR_COL_ADDR_WIDTH : positive := 9; --
constant LMR_REG_BASE : natural := 0;
constant LMR_REG_EXTENDED : natural := 1;
constant LMR_OP_NORMAL : natural := 0;
constant LMR_OP_RES_DLL : natural := 2;
constant LMR_BT_SEQ : natural := 0;
constant LMR_BT_ILVD : natural := 1;
constant LMR_BL2 : natural := 1;
constant LMR_BL4 : natural := 2;
constant LMR_BL8 : natural := 3;
constant LMR_CL2 : natural := 2;
constant LMR_CL3 : natural := 3;
constant LMR_CL2_5 : natural := 6;
-- DDR SDRAM Hardware defined constants
constant BIT_AUTO_PRE : positive := 10; -- bit-position in column address for auto precharge (see Data Sheet)
constant BIT_PRE_ALL : positive := 10; -- bit-position in column address for precharge all (see Data Sheet)
constant ENABLE_PRE_ALL : std_logic := '1';
constant ENABLE_AUTO_PRE : std_logic := '0';
-- DDR-SDR TIMING constants ------------------------------------------------------------------
-- After REFRESH_CLOCKS a refresh cycle is necessary, 64ms / 8192 = max every 7.8125 us refesh
constant REFRESH_INTERVAL : real := 7.8125E-6; -- [s]
-- These values are for your SDRAM part (see datasheet)
constant TCAS : positive := 2; -- CAS latency [clocks]
constant TRP : real := 20.0E-9; -- precharge command period [s]
constant TRAS : real := 45.0E-9; -- active to precharge delay [s]
constant TRFC : real := 75.0E-9; -- auto refresh command period [s]
constant TMRD : positive := 2; -- load mode register command cylce time [clocks]
constant TRCD : real := 20.0E-9; -- active to read or write delay [s]
constant TWR : real := 15.0E-9; -- write recovery time [s]
constant PWR_UP_WAIT : real := 220.0E-6; -- [s]
subtype user_tag_t is unsigned(3 downto 0);
----------------------------------------------------------------------------------------------
end sdram_config;