| ??? 04/28/08 15:08 Read: times |
#154111 - WDO Pin -- Responding to: ???'s previous message |
ADM696 / ADM697
When your MCU wakes up at its reset vector have it check the WDO status via a port pin. If this is low before the program starts to toggle the WDI pin then you know your reset was caused by a watchdog timeout. Internal to the part there is a coupling to the LOW LINE# output that resets the WDO pin so if the watchdog timeout occurs in conjunction with a low voltage condition (or at least leads to the low voltage condition) then the code that subsequently checks the WDO pin will conclude that the reset was due to a power low or power cycle. Note to succcessfully use this part in the manner described then it is necessary to provide a pullup or pulldown on the WDI pin. This pin on these parts is a 3-level pin and if left open or at mid supply the watchdog function is disabled. With a proper pullup it will override the thing that happens to the MCU port pin when it gets reset which is that the pin you are using to drive WDI reverts to an input on most MCUs at reset. The high impedance of the MCU pin may very well put the ADM696/697 into the watchdog disabled state if there was not a strong enough pullup or pulldown. Michael Karas |
| Topic | Author | Date |
| Watchdog/Supervisor with diagnostics? | 01/01/70 00:00 | |
| no, but | 01/01/70 00:00 | |
| Chip numbers? for Silabs Please. | 01/01/70 00:00 | |
| here | 01/01/70 00:00 | |
| Irony | 01/01/70 00:00 | |
| all of them | 01/01/70 00:00 | |
| An osci can tremendously help | 01/01/70 00:00 | |
| Wrong end of the stick? | 01/01/70 00:00 | |
| I would ..... | 01/01/70 00:00 | |
| Check Out These | 01/01/70 00:00 | |
| WDO Pin -- | 01/01/70 00:00 | |
| X5043 from intersil | 01/01/70 00:00 | |
| OK, but where's the diagnostics? | 01/01/70 00:00 | |
| The parts that I linked to can distinguish.... | 01/01/70 00:00 | |
| Sure, but... | 01/01/70 00:00 | |
The Intersil Parts - Not | 01/01/70 00:00 |