- Multiplexor:
- A multiplexor switch
N inputs onto
one output
Example:
- A multiplexor switch
N inputs onto
one output
- Syntax:
Mux ( Coord, Controls, Inputs, Outputs ) Coord = coordinate of the component Controls = control signals of the Mux Inputs = input signals of the Mux Outputs = output signals of the MuxRequirement:
- The number of input signals nust be equal to 2k where k is the the number of control signals
- Example:
void simnet() { Sig(i0,1); Sig(i1,1); Sig(i2,1); Sig(i3,1); // Input signals Sig(c0,1); Sig(c1,1); // Control signals Sig(out,1); // Output signal Switch( "aa", i3, '3', Zero ); Switch( "ba", i2, '2', Zero ); Switch( "ca", i1, '1', Zero); Switch( "da", i0, '0', One ); Switch( "fa", c1, 'b', Zero ); Switch( "ga", c0, 'a', Zero ); /* ========================================== c1 c0 Output -------------------------- 0 0 i0 0 1 i1 1 0 i2 1 1 i3 ========================================== */ Mux ( "ab-db", (c1,c0), (i3,i2,i1,i0), out ); // Mux !!! Probe ( "bc", out ); // Probe out }Notice that:
- There are k = 2
control signals:
- c0 and c1
- Correspondingly,
there are
2k
input signals:
- i0, i1, i2 and i3
-
Otherwise, the
simulation
will report an error:
I/O length error--Mux
Sample output:
- There are k = 2
control signals:
- Example Program:
(Demo above code)
- Prog file: click here
How to run the program:
- Right click on link and
save in a scratch directory
- To compile: cs355sim mux1
- To run: ./simex
- Multiplexing a group
of signals
- The multiplexor component
in the logic-sim simulator is
a
special
multi-inputs
multiplexor
- In general, you can use
an group of
signals as
inputs and
outputs
In other words:
Syntax: Mux ( Coord, Controls, Inputs, Outputs );You can use groups of signals for Inputs and Outputs
- The multiplexor component
in the logic-sim simulator is
a
special
multi-inputs
multiplexor
- What do I mean:
- You have seen a multiplexor
multipexing one signal:
Mux ( "ab-db", (c1,c0), (i3,i2,i1,i0), out );
(BTW, this is the same as: Mux ( "ab-db", (c1,c0), (i3[0],i2[0],i1[0],i0[0]), out[0] );
- We can multiplex
a group of
2 signals
at the same time:
Mux ( "ab-db", (c1,c0), ( (i7,i6), (i5,i4), (i3,i2), (i1,i0) ), (out1, out0) ) ;
Effect:
- If (c1=0,c0=0), the output (out1,out0) is equal to (i1,i0)
- If (c1=0,c0=1), the output (out1,out0) is equal to (i3,i2)
- If (c1=1,c0=0), the output (out1,out0) is equal to (i5,i4)
- If (c1=1,c0=1), the output (out1,out0) is equal to (i7,i6)
- You have seen a multiplexor
multipexing one signal:
- Example:
void simnet() { Sig(i0,1); Sig(i1,1); Sig(i2,1); Sig(i3,1); // Input signals Sig(i4,1); Sig(i5,1); Sig(i6,1); Sig(i7,1); Sig(c0,1); Sig(c1,1); // Control signals Sig(out0,1); Sig(out1,1); // Output signals Switch( "aa", i7, '7', Zero ); Switch( "aa", i6, '6', Zero ); Switch( "ba", i5, '5', Zero ); Switch( "ba", i4, '4', One ); Switch( "ca", i3, '3', One); Switch( "ca", i2, '2', Zero); Switch( "da", i1, '1', One ); Switch( "da", i0, '0', One ); Switch( "fa", c1, 'b', Zero ); Switch( "ga", c0, 'a', Zero ); /* ========================================== c1 c0 Output -------------------------- 0 0 (i1,i0) 0 1 (i3,i2) 1 0 (i5,i4) 1 1 (i7,i6) ========================================== */ Mux ( "ab-db", (c1,c0), ( (i7,i6), (i5,i4), (i3,i2), (i1,i0) ), (out1,out0) ); // Mux !!! Probe ( "bc", out1 ); // Probe out Probe ( "bc", out0 ); // Probe out }
- Example Program:
(Demo above code)
- Prog file: click here
How to run the program:
- Right click on link and
save in a scratch directory
- To compile: cs355sim mux2
- To run: simex