Skip to main content

Interfacing (RAM) Onboard M4K memory blocks of Cyclone II Altera De1 board

This code shows how to store or interface the SRAM with any of your code. You can integrate this code in your projects for storing data. I will upload the interface of RAM with RTC code I designed for storing Date.

In this code I used the on-board M4K memory blocks on Altera DE1 board as RAM in 32 words i.e. 32 address locations of 4-bit. The RAM is initialized through Altera's MegaFunction IP Library. Comment if you don't know how to initialize RAM on any Altera board. I stored some variables like 2,4,6,8 on some starting locations to check if its working. I also added feature of manual address incrementation and data i/p.

For manual data entry you have to use four switches on Altera De1 board viz.
  • SW0 --LSB
  • SW1
  • SW2
  • SW3 --MSB
To write data press KEY3 and to increment address location press KEY0.

Read operation will be done Automatically, as I have interfaced the BCD to 7SEG (modified seg7.vhd in my previous posts) decoder directly to data out of RAM. You will get to see the stored digit on 7Seg display no.1.

You can directly interface the write enable, I/P and O/P of data and address in your code with only some minor changes.

If you have any qurries feel free to Comment directly on post instead of mailing me so other people will also get some help from it. You still can mail me your querries and Ideas at

Download liks:
  • Main Entity sram_test.vhd     : sram_test.vhd
  • Altera DE1 Quartus .sof file  : sram.sof
  • Megafunction file                  : srm.vhd
  • Seg7 modified                      : seg7.vhd



  1. Can you add your top module that sets up the buttons and calls the entity?


Post a Comment

Popular posts from this blog

VHDL code for Clock Divider

This is a clock divider code, just set the max-count value as per your requirenment.

For ex. If I want 1Hz freq. set the max count to i/p freq value viz.
1sec = 1Hz
Then, to get time period of 1sec i.e. 1 Hz frequency set max-count to 240000 as shown below:

1sec  =  24000000  -- for i/p frequency of 24 MHz.

To get your desired frequency just calculate the maxcount with the formula given below:

max_count = 24000000 * (1/your required frequency)


1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48libraryIEEE; useIEEE.STD_LOGIC_1164.ALL; useIEEE.numeric_std.all; entityclk_divisPort ( Clk :instd_logic; rst :instd_logic; op :outstd_logic ); endclk_div; architecturebehavioralofclk_divisconstant max_count :natural:=24000000; -- I used 24MHz clockbeginprocess(Clk,rst) variable count :naturalrange0to max_count; beginif rst ='0'…

0 to 9999 bcd counter on seven segment(VHDL code) Synthesizeble

--Note: while building Project do include sec_clk and seg7 files which i posted

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;
use ieee.std_logic_unsigned.all;

entity c09 is
port( rst,clk: in std_logic;
      op0,op1,op2,op3: out std_logic_vector(6 downto 0));
end c09;

architecture count of c09 is

component sec_clk
Port (
           clk             : in  std_logic;
           rst : in std_logic;
           op  : out std_logic
    end component;

component seg7
port(m: in integer range 0 to 15;
     num: out std_logic_vector(6 downto 0));
end component;

signal flag: std_logic;
signal a: integer range 0 to 10;
signal b: integer range 0 to 10;
signal c: integer range 0 to 10;
signal d: integer range 0 to 10;

c1: sec_clk port map(clk,rst,flag);

variable m0: integer range 0 to 10:=0;
variable m1: integer range 0 to 10:=0;
variable m2: integer range 0 to 10:=0;
variable m3: integer range 0 to 10:=0;


if rst='0' then

16x2 LCD Controller in VHDL

Hello Everybody. The LCD 16x2 code is ready. Just one bug which is still not recognized. You need to program code 2 times on board to see it work. I dont know why its behaving like that.

The text data is stored in a HEX file and is loaded onto the ROM of 32x8 byte size. It can be reconfigured easily.

I will be uploading code in short of time with some new features.

And after that be ready for a BMP decoder. Get ready with your pic to be seen on Monitor via FPGA.


I didnt made  changes to code, if you program fpga 2 times without turning it off the code works(It worked on my DE1 board)
I have uploaded project compiled for DE1 board, mail me your quiries, and if anyone finds bug in code.

Project zip Download: