blocks resolved signals signal guards tri-state buses
DESCRIPTION
Blocks Resolved Signals Signal GUARDs Tri-State Buses. Sequential versus Concurrent Statement in Simulation Cycle. Blocks. Blocks are used for hierarchical partitioning. Blocks. Nested Blocks. Blocks. Guarded Blocks. Guard. Signal GUARD. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/1.jpg)
•Blocks
•Resolved Signals
•Signal GUARDs
•Tri-State Buses
![Page 2: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/2.jpg)
Sequential versus Concurrent Sequential versus Concurrent Statement in Simulation CycleStatement in Simulation Cycle
![Page 3: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/3.jpg)
BlocksBlocks Blocks are used for Blocks are used for hierarchical hierarchical partitioningpartitioning
![Page 4: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/4.jpg)
BlocksBlocks
![Page 5: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/5.jpg)
Nested BlocksNested Blocks
![Page 6: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/6.jpg)
BlocksBlocks
![Page 7: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/7.jpg)
Guarded BlocksGuarded Blocks
![Page 8: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/8.jpg)
GuardGuard
![Page 9: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/9.jpg)
Signal GUARDSignal GUARD
• A block statement may have a guard expression.
Latch: blocblockk(CK'EVENT and CK='1')
begin
Q <= guarded D after 10ns;
end block latch;
![Page 10: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/10.jpg)
• Latch: block(CK'EVENT and CK='1') begin Q <= guarded D after 10ns; end block latch;
• A block statement with guard expression implicitly declares a signal named GUARD.
• The value of GUARD is always updated to the current value of the guard expression.
• Guarded signal assignments implicitly reference to the signal GUARD.
• Signal GUARD may also be explicitly referenced like other signals.
![Page 11: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/11.jpg)
Signal GUARD (cont’d)Signal GUARD (cont’d)
• The equivalent description to the above is the following:
Latch: block(CK'EVENT and CK='1') begin Q <= guarded D after 10ns; end block latch;
![Page 12: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/12.jpg)
Guard ExpressionGuard Expression
![Page 13: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/13.jpg)
Guarded Signal Guarded Signal AssignmentsAssignments
![Page 14: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/14.jpg)
Guarded Signal KindsGuarded Signal Kinds
![Page 15: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/15.jpg)
DisconnectsDisconnects
![Page 16: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/16.jpg)
DriversDrivers
![Page 17: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/17.jpg)
Resolved Resolved SignalsSignals
![Page 18: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/18.jpg)
Resolved SignalsResolved Signals• A signal which has more than one source is
called a resolved signal (outputs can be tied together).
• Such signals are used to model wired-logic or tri-state busses.
• A resolved signal must have a resolution function associated with it.
![Page 19: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/19.jpg)
Resolution FunctionResolution Function• A resolution function takes a one-dimensional,
unconstrained array of values of the resolved type and returns a value of the resolved type.
• You can associate the resolution function with a signal in:– the type declaration – or the signal declaration.
![Page 20: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/20.jpg)
An An example of example of
resolved resolved signalssignals
We add resolution We add resolution function wand to the function wand to the package wired_logicpackage wired_logic
See See explanationexplanation
We define theWe define the wired andwired and logic logic herehere
![Page 21: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/21.jpg)
Resolved Resolved signalsignal
Now that my Now that my signal wand is signal wand is resolved, I am resolved, I am using S1 without using S1 without conflict because conflict because the system the system knows how to knows how to interpret interpret several several assignments on assignments on one signalone signal
use work.wired_logic.all;use work.wired_logic.all;
Resolution function wand is declared Resolution function wand is declared
![Page 22: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/22.jpg)
Tri-State Bus ExampleTri-State Bus Example
• Another example of resolution function and resolved signals
![Page 23: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/23.jpg)
Tri-State Tri-State Function Function DefinitionDefinition
Resolution Resolution functionfunction
Resolved Resolved variablevariable
This slide shows how to This slide shows how to define resolution function tri_statedefine resolution function tri_state
in package four_valued_logicin package four_valued_logic
![Page 24: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/24.jpg)
Definition and use of resolution function in Definition and use of resolution function in Tri-State Bus Example (cont’d)Tri-State Bus Example (cont’d)
Now that it is defined, we Now that it is defined, we can use itcan use it
Because we Because we know know system_bus system_bus is tri_state is tri_state fvl we can fvl we can have many have many assignments assignments on iton it
![Page 25: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/25.jpg)
Resolution FunctionResolution Function
![Page 26: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/26.jpg)
Resolution FunctionResolution Function
![Page 27: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/27.jpg)
Using Resolution Function for Three Using Resolution Function for Three State BusState Bus
![Page 28: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/28.jpg)
Driver ResolutionDriver Resolution
![Page 29: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/29.jpg)
Driver Resolution ConflictDriver Resolution Conflict
![Page 30: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/30.jpg)
Example of Bus Resolution FunctionExample of Bus Resolution Function
![Page 31: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/31.jpg)
Example of Bus Resolution Function Example of Bus Resolution Function ContinuedContinued
![Page 32: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/32.jpg)
Example of Bus Resolution Function Example of Bus Resolution Function ContinuedContinued
![Page 33: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/33.jpg)
Resolution Function Resolution Function for Subtypefor Subtype
![Page 34: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/34.jpg)
Summary on Resolution Summary on Resolution FunctionsFunctions
![Page 35: Blocks Resolved Signals Signal GUARDs Tri-State Buses](https://reader035.vdocuments.mx/reader035/viewer/2022062321/56813c0d550346895da57e62/html5/thumbnails/35.jpg)
SourcesSources• Krzysztof Kuchcinski
• California State University Northridge