Positive and Negative Edge Detector Circuit

Positive and negative edge detection is a common requirement in microprocessors. One application could be to detect edge/level triggered events on certain GPIO inputs. Here i will show you a simple circuit which is use to detect Positive as well negative edges.

VHDL CODE : 

library ieee;
use ieee.std_logic_1164.all;
entity edge is
   port (
    inp        : in  std_logic;         -- inpit
    clk        : in  std_logic;         -- clock
    rst        : in  std_logic;         -- reset
    edge_op : out std_logic);        -- setected edge output
 end edge;

architecture edge_ar of edge is
  signal sig1 : std_logic;              -- signal from 1st flop
  signal sig2 : std_logic;              -- signal from 2nd flop

begin  -- edge_ar
   edge : process(clk, rst)
  begin
    if rst = '1' then
      sig1 <= '0';
      sig2 <= '0';
    elsif clk'event and clk = '1' then
      sig1 <= inp;
      sig2 <= sig1;
    end if;
  end process edge;

  edge_op <= sig1 xor sig2;

end edge_ar;

McAfee Common Framework returned error fffff95b @ 2. (FrameworkManifest.xml corrupt)

Problem 1

The following errors occur after initiating an AutoUpdate:

McAfee Common Framework returned error fffff95b @ 2. (FrameworkManifest.xml corrupt)

Failed to initialize common updater subsystem

Make sure the McAfee Framework Services is running

Problem 2

There are subsequent errors when trying to start the McAfee Framework Service:

Could not start the McAfee Framework Service on Local Computer

The system cannot find the file specified

Problem 3

 Any of the following update methods will result in the AutoUpdate error:

• 
  
  Right-clicking the McShield icon in the system tray and selecting Update Now
• 
  
  Right-clicking the AutoUpdate in the VirusScan Console and clicking Start
• 
  
  Creating a new scheduled task
• 
  
  Editing the properties of the existing AutoUpdate task

Cause

FrameworkManifest.xml has become corrupted.

Solution 1

McAfee Agent 4.0

Changes in the design of the McAfee Agent 4.0 will prevent the corruption of the FrameworkManifest.xml file.

To download the McAfee Agent from the www.mcafee.com website, see KB54808.

Solution 2

 Common Management Agent

Solution 1 - Obtain FrameworkManifest.xml from another computer:

1. 
   
   Locate another VirusScan Enterprise (VSE) computer where the updates are working without error.
2. 
   
   Copy the FrameworkManifest.xml from the following path:
   For VSE 8.5i  (running on Windows Vista)
   x:\Program Data\McAfee\Common Framework 
   
   For VSE 8.5i (running on Windows XP and earlier)x:\Documents and Settings\All Users\Application Data\McAfee\Common Framework
   For VSE 8.0i (running on Windows XP and earlier)x:\Documents and Settings\All Users\Application Data\Network Associates\Common Framework
   
3. 
   
   Paste the file to portable media or a network share that can be accessed by both computers.
4. 
   
   Click Start, Run, type services.msc, and click OK.
5. 
   
   Right-click McAfee Framework Service and select Stop.
6. 
   
   Copy FrameworkManifest.xml to the Common Framework directory.
7. 
   
   Right-click McAfee Framework Service and select Start.
8. 
   
   Update the product.

Solution  2 - Delete FrameworkManifest.xml and reinstall the Common Management Agent (CMA):

It is necessary to delete FrameworkManifest.xml because it may not be removed or replaced when an uninstall/re-install is undertaken.

Step 1 - Allow VSE files and settings to be modified (VirusScan Enterprise 8.5i and higher only)

1. 
   
   Click Start, Programs, McAfee, VirusScan Console.
2. 
   
   Right-click Access Protection, then select Properties.
3. 
   
   Select Common Standard Protection.
4. 
   
   Select Prevent modification of McAfee files and settings and disable this option.
5. 
   
   Click OK.

Step 2 - Delete FrameworkManifest.xml and reinstall CMA

1. 
   
   Delete FrameworkManifest.xml from the following path:
   
   For VSE 8.5i (running on Windows Vista)
   x:\Program Data\McAfee\Common Framework 
   
   For VSE 8.5i (running on Windows XP and earlier)x:\Documents and Settings\All Users\Application Data\McAfee\Common Framework
   For VSE 8.0i (running on Windows XP and earlier)x:\Documents and Settings\All Users\Application Data\Network Associates\Common Framework
   
2. 
   
   Restart your computer.
3. 
   
   Re-install the Common Management Agent (CMA) / ePO agent.

What is Clock Skew?

Given two sequentially-adjacent registers, Ri and Rj, and an equipotential clock distribution network, the clock skew between these two registers is defined as

Tskew-i,j = Tci - Tcj

where Tci and Tcj are the clock delays from the clock source to the registers Ri and Rj, respectively.