Charging a 240mAh 3v7 nominal battery, we get oscillating BAT signals when the battery is fully charged, or close to it. This was first detected because we use a voltage circuit to measure remaining voltage in the battery (by disabling /CE) and then expect OUT to come from the battery. This only happens when IN is energized (to 5v0).
As you can see in the attached scope measurement of BAT1, it should normally be at about 4.2 but cycles at somewhat repeatable intervals. This is over a 10 second interval. Sometimes the battery will just show it's nominal (3v7) value.
- ISET - 5.9k
- ITERM - 6.81k
- TMR - 56k
- ILM - 3.09k
- EN1 - gnd
- EN2 - BAT