Microcontroller having special mode enable detection circuitry and a method of operation therefore
US5991910A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 29, 1997 |
| Grant date | Nov 23, 1999 |
| Priority date | — |
| Expiry date | Oct 29, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F1/22
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
A free-running microcontroller (i.e., one without any reset signal) is shown with special mode enable detect logic for placing the microcontroller into the test or special operations mode, without the benefit of a dedicated pin for such purposes. Rather, the instant invention implements the methodology of first applying a test voltage to indicate to the free-running microcontroller that the test mode is to be entered. Since the device has no reset signal to interrupt normal operation once it has begun, the test voltage is applied before the power supply V.sub.DD to ensure that the device enters test mode before it can enter normal operation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.