MATLAB: How to show the hex or binary representation for an integer or fixed-point signal in Simulink

binaryFixed-Point Designerhexoctalsimulink

When designing or debugging integer or fixed-point algorithms, there are many cases where it is helpful for the display of values to show their hexidecimal or binary representations. How do I get the display of a signal in Simulink to show my preference of hex or binary?

Best Answer

Simulink provides two ways to show hex and binary of signals, Display Block, and Simulink Value Display (yellow boxes).

To do the same in MATLAB click here.

Method 1: Using Display Blocks to show Binary and Hex

The dialogs for Display Blocks provide nine options for Numeric display format. These include hex, binary, decimal, and octal.

You'll notice that 4 options contain the postfix text '(Stored Integer)'.

That relates to the scaling equation

RealWorldValue = StoredIntegerValue * Slope + Bias

Real World Value is in units familiar to the human engineer.

Stored Integer is the value that's actually stored in the computer memory.

A special case is binary point scaling where Bias = 0 and Slope = 2^-FractionLength, so

RealWorldValue = StoredIntegerValue * 2^-FractionLength

Another special case are integers where Slope = 1 and Bias = 0,

so the equation is Trivial

RealWorldValue = StoredIntegerValue

and the two values are identical.

This model was configured such that

1st and 5th display blocks use long format (implies Real World Value).

2nd and 6th display blocks use decimal (Stored Integer) format.

3rd and 7th display blocks use hex (Stored Integer) format.

4th and 8th display blocks use binary (Stored Integer) format.

When we simulate the model, we notice a few things about the Display blocks.

In the 2nd, 3rd, and 4th, display blocks, we see that the text '(SI)' comes before the value.

This is indicating that the Stored Integer is being shown.

The 6th, 7th, and 8th, display blocks, could show the '(SI)' prefix, but do not.

For these blocks, the input is integer so Real World Value and Stored Integer Value are equal.

Thus the '(SI)' prefix is not needed to disambiguate the two kinds of values and is omitted.

Method 2: Using Simulink Display Values (yellow boxes) to Show Binary and Hex

There is another way to display Stored Integer binary, hex, decimal, or octal is Simulink Display Values. You'll remember these as the yellow boxes that appear under Simulink signals.

To turn on this capability, use the toolstrip Debug Tab.

After Toggle option is checked (i.e. ON), click the signal lines where you want the yellow boxes to be shown.

Next go back to the toolstrip Debug tab to open the Value Displays: Options dialog.

There in the lower right of the Options dialog, you will see the same 9 format choices from the Display Block.

After the Display Format is set to the desired value, close the dialog and simulate the model.

The yellow boxes will show your choice of format.

However, there is a known limitation. Six integer types int8, uint8, int16, uint16, int32, and uint32 do not display hex, binary, or octal in the yellow boxes. For these six exceptions, you will need to use the Display Block if you want to see hex, octal, or binary.

Related Solutions

MATLAB: How to show the hex or binary representation for an integer or fixed-point variable in MATLAB

Use of MATLAB's format command and/or Fixed-Point Designer's fipref object can be use to achieve hex display, binary display, or even octal display.

To see instructions for Simulink click here.

Hex display method 1: format hex

To have the MATLAB Command Window show hex representations of all types of variables, not just integer and fixed-point, the format command can be used.

format hex
a = int8([35,-3])
b = fi(a)

a =
  1×2 int8 row vector
   23   fd
   
b = 
23   fd
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 8
        FractionLength: 0

But keep in mind that this also affects other variables types like double and single.

c = single(pi)

c =
  single
   40490fdb

Hex display method 2: fipref.NumberDisplay

For fixed-point fi-objects, an alternate way to have the MATLAB Command Window show hex representations is to use fipref.

format long % restore format for everything else
fpr = fipref;
fpr.NumberDisplay = 'hex'
d = fi([35,127;-1,-128],1,8,0)

fpr = 
         NumberDisplay: 'hex'
    NumericTypeDisplay: 'full'
         FimathDisplay: 'full'
           LoggingMode: 'Off'
      DataTypeOverride: 'ForceOff'
      
d = 
23   7f
ff   80
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 8
        FractionLength: 0

Note, that fipref does not affect doubles, singles, int8 or any other class, only fi objects.

a = int8([35,-3])
c = single(pi)

a =
  1×2 int8 row vector
    35    -3
    
c =
  single
   3.1415927

Binary display method: fipref.NumberDisplay

For fixed-point fi-objects, fipref can be used to have the MATLAB Command Window show binary, hex, or even octal representations.

fpr = fipref;
fpr.NumberDisplay = 'bin'
d = fi([35,127;-1,-128],1,8,0)

fpr = 
         NumberDisplay: 'bin'
    NumericTypeDisplay: 'full'
         FimathDisplay: 'full'
           LoggingMode: 'Off'
      DataTypeOverride: 'ForceOff'
      
d = 
00100011   01111111
11111111   10000000
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 8
        FractionLength: 0

Quick trick to display binary for MATLAB integers.

To show binary for a MATLAB integer such as int8 or uint64, an easy trick is to use fipref and convert the integer to its fixed-point equivalent. Converting to the fi equivalent is the trivial effort of calling fi()

fpr = fipref;
fpr.NumberDisplay = 'bin';
myInt64Var = int64([14;-1;-5;realmax])
fi(myInt64Var)

myInt64Var =
  4×1 int64 column vector
                     14
                     -1
                     -5
    9223372036854775807
    
ans = 
0000000000000000000000000000000000000000000000000000000000001110
1111111111111111111111111111111111111111111111111111111111111111
1111111111111111111111111111111111111111111111111111111111111011
0111111111111111111111111111111111111111111111111111111111111111
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Signed
            WordLength: 64
        FractionLength: 0

In R2017a and later, the conversion of a built-in integer to it's fi equivalent does NOT require a Fixed-Point Designer license. However, it does require that your MATLAB installation include MATLAB Coder OR Simulink OR Fixed-Point Designer.

Note: hex or binary display of fi is stored integer

But aware that the binary or hex display is of the fi object's stored integer value. Recall that for binary-point scaling.

RealWorldValue = StoredIntegerValue * 2^-FractionLength

And, in general

RealWorldValue = StoredIntegerValue * Slope + Bias

y = fi( 35*2^-5, 0, 8, 5 )

y = 
00100011
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 8
        FractionLength: 5

Restoring normal display of values

To restore normal display of values, use MATLAB's format command and fipref.

format long % or short or long g or ...
fpr = fipref;
fpr.NumberDisplay = 'RealWorldValue';
a = int8(37)
b = single(pi)
c = fi( 35*2^-5, 0, 8, 5 )

a =
  int8
   37
b =
  single
   3.1415927
c = 
   1.093750000000000
          DataTypeMode: Fixed-point: binary point scaling
            Signedness: Unsigned
            WordLength: 8
        FractionLength: 5

MATLAB: Is it possible to have a block in Simulink which can create a binary representation of a fixed point object in Simulink 7.3 (R2009a)

The attached model 'example_model.mdl' creates a binary representation of a fixed point object. When you simulate it, it will provide you with the required binary representation values.

To achieve this, you need to select the 'Display' block in the model and then set the property from the MATLAB command line as follows:

set_param(gcb, 'Format', 'binary (Stored Integer)')

Another approach would be to double click on the 'Display' block, click on the drop-down list of the 'Format', and select the 'binary( Stored Integer)' option.

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Related Solutions

MATLAB: How to show the hex or binary representation for an integer or fixed-point variable in MATLAB

MATLAB: Is it possible to have a block in Simulink which can create a binary representation of a fixed point object in Simulink 7.3 (R2009a)

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