What to do about low battery condition. | Cypress Semiconductor
What to do about low battery condition.
As we know, these chips dont have any Low Voltage Detection (which is a poor omission IMHO).
In a device which has a built-in battery, care needs to be taken to ensure the code does not get stuck when the battery gets low, meaning that the device still will not operate when the battery is charged again.
Its possible to implement a battery voltage monitor by using an ADC but this does not seem to be a very reliable method, and seems wasteful of battery power to do this check on a regular basis. The device would need to be woken the the check made and put to sleep again if still OK.
I am wondering what others have done, Is it reliable to simply rely on the watchdog timer, or would there be timing holes during which the watchdog would not fire and reset the code if it crashes owing to low battery? I am not sure what exactly happens to the CPU when a low voltage condition exists. Maybe there is no need to worry about this situation at all.
Or does the radio drop out first? Any thoughts welcome.