## #5 Procedural Logic [Post Homework Here]

Talk about the fifth PyroEDU course here.
ThePyroElectro
Posts: 1181
Joined: Mon Nov 12, 2007 9:24 pm
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### #5 Procedural Logic [Post Homework Here]

A new lesson was posted today:
http://www.pyroelectro.com/edu/fpga/procedural_logic/

Bingo600
Newbie Pyro
Posts: 75
Joined: Sat Jun 28, 2014 7:22 am

### Re: #5 Procedural Logic [Post Homework Here]

Hi Chris

Here is my homework

HOMEWORK QUESTION 1
What is the difference between combinatorial logic and procedural logic?

Combinatorial logic always runs.
Procedural logic runs when a signal on the sensitivity list changes.

HOMEWORK QUESTION 2
What is the purpose of using a ‘sensitivity list’ in a procedural logic process?

To "trigger" the procedure.
Meaning that the procedural statements are only executed when one of the signals in the sensitivity list changes.

HOMEWORK QUESTION 3
Using VHDL make a logic element with one clock input and one output. Then use procedural
logic to divide the clock input frequency by 4 and send it to the output.

Code: Select all

library ieee;
use ieee.std_logic_1164.all;

entity lesson5a is
port(
clk:         in   std_logic; --
clk_out:      out std_logic --
);
end lesson5a;

architecture rtl of lesson5a is
signal f2: std_logic;
signal f4: std_logic;

begin
DIV2: process(clk)
begin
if rising_edge(clk) then
f2 <= not f2;
end if;
end process DIV2;

DIV4: process(f2)
begin
if rising_edge(f2) then
f4 <= not f4;
end if;
end process DIV4;
clk_out <= f4;
end rtl;

Screenshot-RTL Viewer - -home-cfo-x-altera-pyro-course-lesson5a-lesson5a - lesson5a.png (44.7 KiB) Viewed 12863 times

/Bingo

ThePyroElectro
Posts: 1181
Joined: Mon Nov 12, 2007 9:24 pm
Location: Earth
Contact:

### Re: #5 Procedural Logic [Post Homework Here]

Bingo600 wrote:Hi Chris

Here is my homework

HOMEWORK QUESTION 1
What is the difference between combinatorial logic and procedural logic?

Combinatorial logic always runs.
Procedural logic runs when a signal on the sensitivity list changes.

HOMEWORK QUESTION 2
What is the purpose of using a ‘sensitivity list’ in a procedural logic process?

To "trigger" the procedure.
Meaning that the procedural statements are only executed when one of the signals in the sensitivity list changes.

...
...
...

/Bingo