Difference between revisions of "VHDL tutorial"
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| Line 33: | Line 33: | ||
| U || X || X || X || X || X || X || X || X | | U || X || X || X || X || X || X || X || X | ||
|} | |} | ||
| + | |||
| + | VHDL Logic States | ||
| + | * U: uninitialized | ||
| + | * X: forcing unknown | ||
| + | * 0: forcing 0 | ||
| + | * 1: forcing 1 | ||
| + | * Z: high impedance | ||
| + | * W: weak unknown | ||
| + | * L: weak 0 | ||
| + | * H: weak 1 | ||
| + | * -: don't care | ||
Revision as of 19:45, 5 July 2007
To be added: a tutorial on VHDL design with a design example (likely the DAC emulator). Also to be included: the VHDL resolution table:
| U | X | 0 | 1 | Z | W | L | H | - | |
|---|---|---|---|---|---|---|---|---|---|
| U | U | U | U | U | U | U | U | U | U |
| X | U | X | X | X | X | X | X | X | X |
| 0 | U | X | 0 | X | 0 | 0 | 0 | 0 | X |
| 1 | U | X | X | 1 | 1 | 1 | 1 | 1 | X |
| Z | U | X | 0 | 1 | Z | W | L | H | X |
| W | U | X | 0 | 1 | W | W | W | W | X |
| L | U | X | 0 | 1 | L | W | L | W | X |
| H | U | X | 0 | 1 | H | W | W | H | X |
| - | U | X | X | X | X | X | X | X | X |
VHDL Logic States
- U: uninitialized
- X: forcing unknown
- 0: forcing 0
- 1: forcing 1
- Z: high impedance
- W: weak unknown
- L: weak 0
- H: weak 1
- -: don't care