I want make a program that can read/write data with sram on de2 board
But I has a trouble with read data! This only can read when I remove " this line" in the code! (I test this with de2 controlpanel) when I don't remove "this line" the program only can write!
library ieee;
use ieee.std_logic_1164.all;
entity sram is
port( clock_50:in std_logic;
sw: in std_logic_vector(17 downto 0);
ledr: out std_logic_vector(15 downto 0);
sram_dq: inout std_logic_vector(15 downto 0);
sram_addr: out std_logic_vector(17 downto 0);
sram_we_n,sram_oe_n,sram_ub_n,sram_lb_n,sram_ce_n: out std_logic
);
end sram;
architecture behavior of sram is
signal clk,w,r: std_logic;
signal datain,dataout: std_logic_vector(15 downto 0);
begin
datain<="00000000"&sw(15 downto 8) ;
sram_addr<="0000000000"&sw(7 downto 0);
ledr<=dataout;
sram_ce_n<='0';
sram_ub_n<='0';
sram_lb_n<='0';
process (sw(17 downto 16),clock_50) is
begin
case sw(17 downto 16) is
--read
when "10" =>
sram_oe_n<='0';
dataout<=sram_dq;
--write
when "01" =>
sram_we_n<='0';
sram_dq<=datain;--- this line
when others =>
sram_oe_n<='1';
sram_we_n<='1';
end case;
end process;
end behavior;
