| (11) | EP 0 477 706 A3 |
(12) | EUROPEAN PATENT APPLICATION |
|
|
|
| |||||||||||||||||||||||||||
(54) | Asynchronous state machine synchronization circuit |
(57) A circuit for sampling a digital input signal utilizing an asynchronous strobe signal and a method for such sampling are disclosed. The circuit includes an input storage element, such as a latch, which stores the input signal upon receipt of a strobe signal. There is a possibility that the input storage element will become temporarily metastable, with the output of the element being indeterminate, should the digital input signal change levels at substantially the time that the strobe signal is received. The subject sampling circuit includes circuitry which senses when the input storage element is metastable and gating circuitry which produces the sample signal after receipt of the strobe signal, provided the input storage element is not metastable. The sample signal can then be used to sample the stored input signal. |