Battery Voltage Monitoring - vcomp_alert - Wake on event

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Xavier
1

My system has only battery power, and I want to get alert when battery level drops.
(To prompt user to replace it, or to shut the system down.)

I’m adding a voltage-monitor (INA226) on my carrier board, and plan to connect its ALERT pin to wake the SOM from SC7 state.

I saw that there’s ‘vcomp_alert_N’ pin, which is ‘detailed/described’ as ‘Voltage Comparator Alert’, and is defined as ‘wake’, and is on VDDIO_SYS, 1.8V. (In pin list of SOM Datasheet v0.9)
In OEM Design Guide 20190614 Table 92 - Jetson AGX Xavier Connector Pin Descriptions - this pin is TBD.

Do I need to have external pull-up, or that one is on the SOM? To which voltage-rail?

I assume that all pins with ‘WAKE’ can be used. Is there any other pin which I should connect to - instead of VCOMP_ALERT_N?

Please refer to the schematic I have prepared.

Thanks.

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2

Hi, your design looks fine, the pull-up is necessary if no in INA226.

3

Thanks for your prompt reply. Can you please add:

"Is there any other pin which I should connect to - instead of VCOMP_ALERT_N? "

regards, Ishay

4

It depends on the design request of INA226 since it is not validated on Xavier, suggest to check with vendor for the reference design and migrate to Xavier.

5

I will rephrase my question:

The SOM has several GPIO pins, and some are defined as WAKE* in the pin list of the SOM Datasheet.
I assume that all pins defindes as ‘WAKE’ can be used to wake the system.
Alternatively, the VCOMP_ALERT_N has some other property, which make it unique - If so, what’s this?

Thanks, Ishay

6

I don’t know what you mean about other property. In theory, any pin with wake function can be used as alert, there is a table (table 13) in OEM DG of wake pins of SC7. Your current selection of Vcomp_alert_n is in it.