| ??? 04/30/05 22:46 Read: times |
#92656 - Noise Symptoms Responding to: ???'s previous message |
Noise problems are not usually encountered during the development phase of a microcontroller system. This is because benches rarely simulate the system's intended environment. Noise problems tend not to show up until the system is installed and operating in its intended environment. Then, after a few minutes or hours of normal operation the system finds itself someplace out in left field. Inputs are ignored and outputs are gibberish. The system may respond to a reset, or it may have to be turned off physically and then back on again, at which point it commences operating as though nothing had happened. There may be an obvious cause, such as an electrostatic discharge from somebody's finger to a keyboard or the upset occurs every time a copier machine is turned on or off. Or there may be no obvious cause, and nothing the operator can do will make the upset repeat itself. But a few minutes, or a few hours, or a few days later it happens again.One symptom of electrical noise problems is randomness, both in the
occurrence of the problem and in what the system does in its failure. All operational upsets that occur at seemingly random intervals are not necessarily caused by noise in the system. Marginal VCC, inadequate decoupling, rarely encountered software conditions, or timing coincidences can produce upsets that seem to occur randomly. On the other hand, some noise sources can produce upsets downright periodically. Nevertheless, the more difficult it is to characterize an upset as to cause and effect, the more likely it is to be a noise problem. Designing Microcontroller Systems for Noisy Environments |
| Topic | Author | Date |
| emi problem? | 01/01/70 00:00 | |
| To Nandhu ! | 01/01/70 00:00 | |
| Insufficient info! | 01/01/70 00:00 | |
| Noise Symptoms | 01/01/70 00:00 | |
| See also | 01/01/70 00:00 | |
| FAQ | 01/01/70 00:00 | |
| My tries | 01/01/70 00:00 | |
| near | 01/01/70 00:00 | |
| one mc and rtc only | 01/01/70 00:00 | |
| coming from where? | 01/01/70 00:00 | |
| ac mains | 01/01/70 00:00 | |
| does that mean averaging | 01/01/70 00:00 | |
not averaging | 01/01/70 00:00 |