| ??? 06/24/03 10:39 Read: times |
#49166 - RE: why no 555 Responding to: ???'s previous message |
The 555 is unable to do the watchdog functionality on a single chip:
A watchdog consist of a transition sensitive retriggerable monoflop followed by a flipflop, which periodically fire an release the reset pin until the watchdog was correct triggered again. So you need many more as only a single 555. Maybe a 74HC123 can do it with some external RC. Also a watchdog should have a defined power on/off behaviour but the 555 or 74HC123 don't have. Peter |
| Topic | Author | Date |
| WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: WDT bigger timeout | 01/01/70 00:00 | |
RE: WDT bigger timeout | 01/01/70 00:00 | |
| RE: why no 555 | 01/01/70 00:00 |