How to implement the wake-up using a pushbutton switch and without connecting the USB on MAX17320?

Thank you, this is helpful.

Since PBen is already programmed in NVM and survives a cold power cycle, I no longer think the issue is related to the pushbutton configuration itself.

Two things stand out:

1. ALRT currently has no pull-up. The pushbutton wake mechanism depends on the ALRT signal transitioning from a valid high level to low. If ALRT is floating during a cold startup, the device may never detect a valid button event. As a first test, I would recommend adding a pull-up on ALRT (for example 100 kΩ, or 47 kΩ if preferred) to an always-available logic rail rather than to a rail that is only present after the system powers up.

2. The cells are connected one at a time. During cold installation the gauge temporarily sees one populated cell and one missing cell. Since the device does not respond on I²C afterward, it is possible that startup is entering an undervoltage-related shutdown condition. The fact that both a charger connection and a 9 V pulse on PCKP can recover the part makes this explanation plausible.

Could you try the following experiments:

• Add a pull-up to ALRT and retest the pushbutton wake.
• Connect the complete 2-cell stack simultaneously (or as close as practical) and check whether pushbutton wake behaves differently.
• Measure ALRT during cold startup and during the button press when you gain access to the oscilloscope.

Two additional questions: when the charger wakes the device and it remains in an error state, which fault bits are being reported in Status/ProtStatus immediately after wakeup? Also are you using your own board or is this implementation on a EVKIT

Best,

Douglas

Thank you, this is helpful.

Since PBen is already programmed in NVM and survives a cold power cycle, I no longer think the issue is related to the pushbutton configuration itself.

Two things stand out:

1. ALRT currently has no pull-up. The pushbutton wake mechanism depends on the ALRT signal transitioning from a valid high level to low. If ALRT is floating during a cold startup, the device may never detect a valid button event. As a first test, I would recommend adding a pull-up on ALRT (for example 100 kΩ, or 47 kΩ if preferred) to an always-available logic rail rather than to a rail that is only present after the system powers up.

2. The cells are connected one at a time. During cold installation the gauge temporarily sees one populated cell and one missing cell. Since the device does not respond on I²C afterward, it is possible that startup is entering an undervoltage-related shutdown condition. The fact that both a charger connection and a 9 V pulse on PCKP can recover the part makes this explanation plausible.

Could you try the following experiments:

• Add a pull-up to ALRT and retest the pushbutton wake.
• Connect the complete 2-cell stack simultaneously (or as close as practical) and check whether pushbutton wake behaves differently.
• Measure ALRT during cold startup and during the button press when you gain access to the oscilloscope.

Two additional questions: when the charger wakes the device and it remains in an error state, which fault bits are being reported in Status/ProtStatus immediately after wakeup? Also are you using your own board or is this implementation on a EVKIT

Best,

Douglas