Experimental phenomenon of ROM usage
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zynq xc7z030 board – FII-PE7030 Experiment 8 – Use of ROM



Experiment 8 Use of ROM

8.1 Experiment Objective

  1. Study the usage of internal memory block of FPGA
  2. Study the format of *.coe and how to edit *.coe file to configure the contents of ROM
  3. Learn to use RAM, read and write RAM

8.2 Experiment Implement

  1. Design 16 outputs ROM, address ranging 0-255
  2. Interface 8-bit switch input as ROM’s address
  3. Segment display illustartes the contents of ROM and require conversion of hexadecimal to BCD output.

8.3 Experiment

8.3.1 Program Design

The first step: the establishment of the main program framework (interface design)

module rom_test(

input inclk_p,

input inclk_n,

input rst,

input [7:0] sw,

output reg [7:0] tube_sel,

output reg [5:0] tube_seg



The second step: call ROM IP core

Refer to experiment 1 and experiment 6, select Block Memory Generator, double-click to enter the setting interface, as shown in Figure 8.1, and set according to the parameters in the figure.

In the Basic window, as shown in Figure 8.1:

  1. Component Name: Component
  2. Memory Type: Signal Port ROM
  3. Others set as default

In the Port A Options window, as shown in Figure 8.2.

  1. Poart A Width: 16
  2. Poart A Depth: 256
  3. Enable Port Type: Always Enabled

ROM setting 1

Figure 8.1 ROM setting 1

ROM setting 2

Figure 8.2 ROM setting 2

Click OK button to generate ROM

The third step: instantiate ROM

reg [15:0] rom_q;

rom_256x16 rom_256x16_inst (

.clka (sys_clk),

.addra (sw),

.douta (rom_q)


The fourth step: create *.coe file and initialize ROM

The .coe file for this experiment was generated based on matlab2018. The *.m file is as follows:

% –by Alex li–

% function : create .coe

clear all;

close all;


depth= 256;

width =16;

fid_s = fopen(‘test_rom.coe’, ‘w+’);

fprintf(fid_s, ‘MEMORY_INITIALIZATION_RADIX = %d;\n’,width);

fprintf(fid_s, ‘%s\n’, ‘MEMORY_INITIALIZATION_VECTOR =’);

for i=0:depth1

data =i*i;


fprintf(fid_s, ‘%s’, b);

fprintf(fid_s, ‘%s\n’, ‘,’);



disp(‘=======mif file completed========’);

The generated *.m file has a depth of 256, the width of each data is 16, and the data is the square of the depth value. *.coe file content and format are shown in Figure 8.3.

Figure 8.3 *.coe file content

Under the Sources window of the Vivado interface, expand the Design Sources folder, double-click to open the ROM created previously, enter the setting interface, under the Other Options window, select the check box Load Init Flie, and click Browse to add the generated *.coe file, such as shown in Figure 8.4, click the OK button to complete the initialization of the ROM.

Figure 8.4 Initialize ROM

The fifth step: comprehensive design

Instantiate all modules and integrate them into the top-level file. Refer to experiment 7 to complete the program design.


8.4 Experiment Verification

The first step: add constraints and assign pins

The pin assignment is the same as that of experiment 7, refer to experiment 7 for more information.

The second step: run the implementation, generate bitstream files, and verify the board

After successfully downloading the generated programmable bitstream file to the Zynq_7030 development board, the experimental phenomenon is shown in Figure 8.5.

When the DIP switch is 0000_0011 (3 in decimal), which means the content in the third byte of the rom will be read out. The segment display illustartes 9 and is the square of 3, which is consistent with the data have been stored.


Experimental phenomenon of ROM usage
Experimental phenomenon of ROM usage

Figure 8.5 Experimental phenomenon of ROM usage



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