generate barcode c#.net Figure 2-8 Delta Delay Evaluation Mechanism in C#.NET

Read Quick Response Code in C#.NET Figure 2-8 Delta Delay Evaluation Mechanism

Figure 2-8 Delta Delay Evaluation Mechanism
Read QR In Visual C#.NET
Using Barcode recognizer for .NET framework Control to read, scan QR-Code image in VS .NET applications.
www.OnBarcode.com
QR Code 2d Barcode Recognizer In Visual C#
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
Time 10 ns (1) Delta
Bar Code Recognizer In C#.NET
Using Barcode recognizer for VS .NET Control to read, scan barcode image in VS .NET applications.
www.OnBarcode.com
Barcode Decoder In C#.NET
Using Barcode recognizer for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
Two
Scan Denso QR Bar Code In C#.NET
Using Barcode scanner for VS .NET Control to read, scan Denso QR Bar Code image in .NET framework applications.
www.OnBarcode.com
QR Code Recognizer In VS .NET
Using Barcode reader for ASP.NET Control to read, scan Quick Response Code image in ASP.NET applications.
www.OnBarcode.com
Activity A <= 0 evaluate inverter B <= 1 evaluate AND evaluate NAND D <= 1 C <= 0 evaluate AND D <= 0
QR Decoder In .NET
Using Barcode recognizer for .NET framework Control to read, scan Quick Response Code image in .NET applications.
www.OnBarcode.com
Recognize QR-Code In Visual Basic .NET
Using Barcode reader for VS .NET Control to read, scan QR Code ISO/IEC18004 image in Visual Studio .NET applications.
www.OnBarcode.com
(4) 11 ns
Barcode Reader In Visual C#.NET
Using Barcode reader for .NET framework Control to read, scan bar code image in VS .NET applications.
www.OnBarcode.com
Decode PDF417 In C#.NET
Using Barcode decoder for Visual Studio .NET Control to read, scan PDF417 image in .NET framework applications.
www.OnBarcode.com
The inverter calculates the new value for signal B, which is the value 1 This value is not propagated immediately, but is scheduled for the next delta time point (delta 2) The simulator then begins execution of delta time point 2 Signal B is updated to a 1 value, and the AND gate and NAND gate are reevaluated Both the AND gate and NAND gate now schedule their new values for the next delta time point (delta 3) When delta 3 occurs, signal D receives a 1 value, and signal C receives a 0 value Because signal C also drives the AND gate, the AND gate is reevaluated and schedules its new output for delta time point 4 To summarize, simulation deltas are an infinitesimal amount of time used as a synchronization mechanism when 0 delay events are present Delta delay is used whenever 0 delay is specified, as shown in the following:
Reading QR In Visual C#.NET
Using Barcode recognizer for .NET framework Control to read, scan QR Code JIS X 0510 image in .NET framework applications.
www.OnBarcode.com
EAN-13 Scanner In Visual C#
Using Barcode reader for VS .NET Control to read, scan GS1 - 13 image in .NET applications.
www.OnBarcode.com
a <= b AFTER 0 ns;
Decode International Standard Book Number In Visual C#.NET
Using Barcode reader for VS .NET Control to read, scan International Standard Book Number image in VS .NET applications.
www.OnBarcode.com
Scan Bar Code In Java
Using Barcode scanner for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Another case for using delta delay is when no delay is specified For example:
Bar Code Decoder In Java
Using Barcode recognizer for Eclipse BIRT Control to read, scan bar code image in BIRT applications.
www.OnBarcode.com
UCC - 12 Decoder In C#
Using Barcode reader for Visual Studio .NET Control to read, scan read, scan image in VS .NET applications.
www.OnBarcode.com
a <= b;
Scanning EAN / UCC - 13 In Objective-C
Using Barcode recognizer for iPhone Control to read, scan EAN 128 image in iPhone applications.
www.OnBarcode.com
Decoding Code 39 In None
Using Barcode recognizer for Online Control to read, scan Code 3 of 9 image in Online applications.
www.OnBarcode.com
In both cases, whenever signal b changes value from an event, signal a has a delta-delayed signal assignment to it An equivalent VHDL model of the circuit shown in Figure 2-6, except for the flip-flop, is shown in the following:
Data Matrix 2d Barcode Scanner In Java
Using Barcode recognizer for BIRT Control to read, scan Data Matrix 2d barcode image in BIRT reports applications.
www.OnBarcode.com
Scan Data Matrix 2d Barcode In C#.NET
Using Barcode recognizer for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
Behavioral Modeling
ENTITY reg IS PORT( a, clock : in bit PORT( d : out bit); END reg; ARCHITECTURE test OF reg IS SIGNAL b, c : bit; BEGIN b <= NOT(a); -- notice no delay c <= NOT( clock AND b); d <= c AND b; END test;
Drivers
VHDL has a unique way of handling multiply driven signals Multiply driven signals are very useful for modeling a data bus, a bidirectional bus, and so on Correctly modeling these kinds of circuits in VHDL requires the concept of signal drivers A VHDL driver is one contributor to the overall value of a signal A multiply driven signal has many drivers The values of all of the drivers are resolved together to create a single value for the signal The method of resolving all of the contributors into a single value is through a resolution function (resolution functions are discussed in 5, Subprograms and Packages ) A resolution function is a designerwritten function that is called whenever a driver of a signal changes value
Driver Creation
Drivers are created by signal assignment statements A concurrent signal assignment inside of an architecture produces one driver for each signal assignment Therefore, multiple signal assignments produce multiple drivers for a signal Consider the following architecture:
ARCHITECTURE test OF test IS BEGIN a <= b AFTER 10 ns; a <= c AFTER 10 ns; END test;
Signal a is being driven from two sources, b and c Each concurrent
Two
signal assignment statement creates a driver for signal a The first statement creates a driver that contains the value of signal b delayed by 10 nanoseconds The second statement creates a driver that contains the value of signal c delayed by 10 nanoseconds How these two drivers are resolved is left to the designer The designers of VHDL did not want to arbitrarily add language constraints to signal behavior Synthesizing the preceding example would short c and b together
Bad Multiple Driver Model
Let s look at a model that looks correct at first glance, but does not function as the user intended The model is for the 4 to 1 multiplexer discussed earlier:
USE WORKstd_logic_1164ALL; ENTITY mux IS PORT (i0, i1, i2, i3, a, b: IN std_logic; PORT (q : OUT std_logic); END mux; ARCHITECTURE bad BEGIN q <= i0 WHEN a q <= i1 WHEN a q <= i2 WHEN a q <= i3 WHEN a END BAD; OF mux IS = = = = 0 1 0 1 AND AND AND AND b b b b = = = = 0 0 1 1 ELSE ELSE ELSE ELSE 0 ; 0 ; 0 ; 0 ;
This model assigns i0 to q when a is equal to a 0 and b is equal to a 0; i1 when a is equal to a 1 and b is equal to a 0; and so on At first glance, the model looks like it works However, each assignment to signal q creates a new driver for signal q Four drivers to signal q are created by this model Each driver drives either the value of one of the i0, i1, i2, i3 inputs or 0 The value driven is dependent on inputs a and b If a is equal to 0 and b is equal to 0 , the first assignment statement puts the value of i0 into one of the drivers of q The other three assignment statements do not have their conditions met and, therefore, are driving the value 0 Three drivers are driving the value 0 , and one driver is driving the value of i0 Typical resolution functions would have a difficult time predicting the desired output on q, which is the value of i0 A better way to write this model is to create only one driver for signal
q, as shown in the following:
Copyright © OnBarcode.com . All rights reserved.