8086/8088 MICROPROCESSOR INT 21h FUNCTIONS

INT 21h - The general function despatcher

Most of the general functions and services offered by DOS are implemented through this interrupt . The functions available are well standardised and should be common to all MSDOS, PCDOS and DOS Plus systems. Well behaved programs, therefore, should use these facilities in preference to any other methods available for the widest range of compatibility.

INT 21h in the 512's implementation of DOS Plus 2.1 provides 77 official functions, two of which are non-functional and return with no action. Within this range some calls have subfunctions which further extend the range of operations.

In all calls, on entry AH defines the function. Other parameters may also be required in other registers. Where a memory block is used by the call this is specified in the normal segment:offset form. In all cases the general programming technique is to set AH to the function pointer, set up the required register contents (and the memory block if necessary) then to issue the call by the assembly code INT instruction. 

MATHWORKS MATLAB COMMANDS

Non-standard Matlab commands are highlighted in green.

Command	Description
abs	Absolute value
acker	Compute the K matrix to place the poles of A-BK, see also place
axis	Set the scale of the current plot, see also plot, figure
bode	Draw the Bode plot, see also logspace, margin, nyquist1
c2dm	Continuous system to discrete system
clf	Clear figure (use clg in Matlab 3.5)
conv	Convolution (useful for multiplying polynomials), see also deconv
ctrb	The controllability matrix, see also obsv
deconv	Deconvolution and polynomial division, see also conv
det	Find the determinant of a matrix
dimpulse	Impulse response of discrete-time linear systems, see also dstep
dlqr	Linear-quadratic requlator design for discrete-time systems, see also lqr
dlsim	Simulation of discrete-time linear systems, see also lsim
dstep	Step response of discrete-time linear systems, see also stairs
eig	Compute the eigenvalues of a matrix
eps	Matlab's numerical tolerance
feedback	Feedback connection of two systems.
figure	Create a new figure or redefine the current figure, see also subplot, axis
for	For, next loop
format	Number format (significant digits, exponents)
function	Creates function m-files
grid	Draw the grid lines on the current plot
gtext	Add a piece of text to the current plot, see also text
help	HELP!
hold	Hold the current graph, see also figure
if	Conditionally execute statements
imag	Returns the imaginary part of a complex number, see also real
impulse	Impulse response of continuous-time linear systems, see also step, lsim, dlsim
input	Prompt for user input
inv	Find the inverse of a matrix
jgrid	Generate grid lines of constant damping ratio (zeta) and settling time (sigma), see also sgrid, sigrid, zgrid
legend	Graph legend
length	Length of a vector, see also size
linspace	Returns a linearly spaced vector
lnyquist1	Produce a Nyquist plot on a logarithmic scale, see also nyquist1
log	natural logarithm, also log10: common logarithm
loglog	Plot using log-log scale, also semilogx/semilogy
logspace	Returns a logarithmically spaced vector
lqr	Linear quadratic regulator design for continuous systems, see also dlqr
lsim	Simulate a linear system, see also step, impulse, dlsim.
margin	Returns the gain margin, phase margin, and crossover frequencies, see also bode
norm	Norm of a vector
nyquist1	Draw the Nyquist plot, see also lnyquist1. Note this command was written to replace the Matlab standard command nyquist to get more accurate Nyquist plots.
obsv	The observability matrix, see also ctrb
ones	Returns a vector or matrix of ones, see also zeros
place	Compute the K matrix to place the poles of A-BK, see also acker
plot	Draw a plot, see also figure, axis, subplot.
poly	Returns the characteristic polynomial
polyadd	Add two different polynomials
polyval	Polynomial evaluation
print	Print the current plot (to a printer or postscript file)
pzmap	Pole-zero map of linear systems
rank	Find the number of linearly independent rows or columns of a matrix
real	Returns the real part of a complex number, see also imag
rlocfind	Find the value of k and the poles at the selected point
rlocus	Draw the root locus
roots	Find the roots of a polynomial
rscale	Find the scale factor for a full-state feedback system
set	Set(gca,'Xtick',xticks,'Ytick',yticks) to control the number and spacing of tick marks on the axes
series	Series interconnection of Linear time-independent systems
sgrid	Generate grid lines of constant damping ratio (zeta) and natural frequency (Wn), see also jgrid, sigrid, zgrid
sigrid	Generate grid lines of constant settling time (sigma), see also jgrid, sgrid, zgrid
size	Gives the dimension of a vector or matrix, see also length
sqrt	Square root
ss	Create state-space models or convert LTI model to state space, see also tf
ss2tf	State-space to transfer function representation, see also tf2ss
ss2zp	State-space to pole-zero representation, see also zp2ss
stairs	Stairstep plot for discreste response, see also dstep
step	Plot the step response, see also impulse, lsim, dlsim.
subplot	Divide the plot window up into pieces, see also plot, figure
text	Add a piece of text to the current plot, see also title, xlabel, ylabel, gtext
tf	Creation of transfer functions or conversion to transfer function, see also ss
tf2ss	Transfer function to state-space representation, see also ss2tf
tf2zp	Transfer function to Pole-zero representation, see also zp2tf
title	Add a title to the current plot
wbw	Returns the bandwidth frequency given the damping ratio and the rise or settling time.
xlabel/ylabel	Add a label to the horizontal/vertical axis of the current plot, see also title, text, gtext
zeros	Returns a vector or matrix of zeros
zgrid	Generates grid lines of constant damping ratio (zeta) and natural frequency (Wn), see also sgrid, jgrid, sigrid
zp2ss	Pole-zero to state-space representation, see also ss2zp
zp2tf	Pole-zero to transfer function representation, see also tf2zp

MATHWORKS MATLAB PRACTICE PROBLEMS

Assignment:

1)

Create an M-file in which you give an input and it displays the table of that number:

Example:

>> “name of m-file”

>> What is your desired number? “Enter 2 or any other”

>> 2x1=2

      2x2=4 and so on…

MATHWORkS MATLAB TUTORIAL AND EXERCISE

MATHWORKS MATLAB: 

Exercise #1: Non-oriented, Center-Surround Receptive Field Model.

Goal: To implement and test a simple RF model in Matlab.

1. MATHWORKS MATLAB Basics

When you start Matlab, it should open with a Command Window.  This window allows you to enter individual commands at the prompt (>>).  Commands can define variables.  For example:

>> x = zeros(100);

creates a 2D array (100x100) and fills it with zeros.  Variables are initialized whenever they appear on the left hand side of an expression.  You do not need to specify the storage type or size, as in other languages.  Variables must be initialized before they are used on the right hand side of an expression.  When variables are initialized they get stored in the Workspace.  You can view the variables in the Workspace by typing:

>> who

You can see the contents of a single variable by typing the variable name at the prompt without a semicolon at the end:

>> x

Commands can also call Matlab functions, e.g.

>> plot(x);

To find out more about the function “plot”, type:

>> help plot

           

If you want to create a program of more than a few lines, it soon becomes very tedious to enter and re-enter commands one at a time.  Therefore, Matlab allows you to create M-files.  M-files are plain text files that contain Matlab expressions and function calls.  M-file names end with the extension “.m”.  Usually, the Command Window has a button that will invoke an M-file editor.  You can type multiple commands into the editor window and save them.  Usually, there will be a button in the editor window that allows you to save and execute the file in one shot.  Otherwise, you  can execute the M-file by typing its name, sans extension, at the command prompt.  E.g. if you created the file “myprog.m”, you would just type:

>> myprog

LABCENTRE ELECTRONICS ISIS PROTEUS TUTORIAL

In this tutorial I am going to tell you about the basics of LABCENTRE ELECTRONICS ISIS PROTEUS .this software is widely used by all the electrical  engineers as it provides a mean for testing their circuits before implementing them practically.

So, first of all let have a look at the opening window of the LABCENTRE ELECTRONICS ISIS PROTEUS.

I am using the LABCENTRE ELECTRONICS ISIS PROTEUS 7.6 .

This is the window which we see when we open the LABCENTRE ELECTRONICS ISIS PROTEUS 7.6.

Lets first become familiar with different icons in it.

  VIRTUAL INSTRUMENT MODE:

 This icon is for measuring the different parameters of the circuit like voltage, current output waveforms etc and. It provides us with AC voltmeter and ammeter and DC voltmeter and ammeter and it has also got the option of the oscilloscope for seeing the different waveforms and a logic analyzer for observing the logic states. It has also got the option of signal generator for providing waveforms of different shapes, different frequencies and different amplitudes.