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