dp_ram.v

ddr ram controller vhdl code

//------------------------------------------------------------------ 
2 // Dual port memory (one read and one write port, same width) 
3 //------------------------------------------------------------------ 
4  
5 module dp_ram #( 
6         parameter adr_width = 11, 
7         parameter dat_width = 8  
8 ) ( 
9         // read port a  
10         input                       clk_a, 
11         input      [adr_width-1:0]  adr_a, 
12         output reg [dat_width-1:0]  dat_a, 
13         // write port b 
14         input                       clk_b, 
15         input      [adr_width-1:0]  adr_b, 
16         input      [dat_width-1:0]  dat_b, 
17         input                       we_b 
18 ); 
19  
20 parameter depth = (1 << adr_width); 
21  
22 // actual ram cells 
23 reg [dat_width-1:0] ram [0:depth-1]; 
24  
25 //------------------------------------------------------------------ 
26 // read port 
27 //------------------------------------------------------------------ 
28 always @(posedge clk_a) 
29 begin 
30         dat_a <= ram[adr_a]; 
31 end 
32  
33 //------------------------------------------------------------------ 
34 // write port 
35 //------------------------------------------------------------------ 
36 always @(posedge clk_b) 
37 begin 
38         if (we_b) begin 
39                 ram[adr_b] <= dat_b; 
40         end 
41 end 
42  
43 endmodule