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Old 05-25-2009, 04:48 PM
wantanjung wantanjung is offline
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Join Date: May 2009
Location: Singapore GMT + 8
Posts: 6
Default VHDL: How to index a std logic vector

Dear guys,

I need some help programming VHDL.

I need to break up a 8bit binary data to 2 4-bit data. Below is a glimpse of the code:

library IEEE;
use ieee.numeric_std.all;
use work.CharLoopController.all;

entity Sub_prog_test is
Port ( en,reset,DisplayData,clk : in STD_LOGIC;
Data: in STD_LOGIC_VECTOR (7 downto 0);
end Sub_prog_test;

architecture Behavioral of Sub_prog_test is


process (clk,en,reset)

variable upper_4bit, lower_4bit: std_logic_vector (3 downto 0);

--------------------Some statement-------------------------

upper_4bit<=Data(7)& Data(6)& Data(5)& Data(4);
lower_4bit<=Data(3)& Data(2)& Data(1)& Data(0);

However, when i do this, i get an error: "Wrong index type for Data."

Please help

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Old 05-27-2009, 05:09 PM
wantanjung wantanjung is offline
New Member
Join Date: May 2009
Location: Singapore GMT + 8
Posts: 6
Default Solution found

Hi guys..

Realised my own mistake. Accidently named 2 variables similarly: 1 is data, other is Data. After changing Data to a new name: DataVar, everything went ok.

Shucks.. I thought VHDL syntax was case sensitive.

Best Regards

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Old 10-20-2009, 02:49 AM
u0508933 u0508933 is offline
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Join Date: Oct 2009
Posts: 1
Default Help with Programming


i am a final year engineering student and i am seeking your help. I am required to design a Mesh Fabric Reference Design using VHDL programming.

please refer to the following document.

sample source code is not available for this and i have to design this from scratch. Would you be willing to help me. There will be good incentives. Please reply if interested. Thanks.
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Old 10-20-2009, 06:27 PM
ridsudcre ridsudcre is offline
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Join Date: Oct 2009
Posts: 1

Oh man, this game is pretty sweet. Why can't more games have cutscenes that you want to see more of?

Conseil financement ********** travaux | Plan de financement credit immo | Calcul financement **********
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