POWER_ON_N pin assert shutting down WP7610 module

While testing the WP7610 module with the provided firmware 13.2 image pulling the POWER_ON_N pin LOW (while our modules are on) is powering our WP7610 modules off.

I can’t find any documentation indicating that this pin will power the module OFF. The datasheets state the pin should only power the module ON when asserted and be ignored if the module is already powered on.

This behaviour is not seen with the WP7609 modules we also use. They work as expected.

Are there any AT commands or config we can change on the WP7610 to ensure the POWER_ON_N pin only functions as an ON button?

From the product technical specification https://source.sierrawireless.com/resources/airprime/hardware_specs_user_guides/airprime_wp76xx_product_technical_specification/. It states that this pin should only be used for emergencies such as when the module stops responding to AT commands, and it must not be toggled or pulsed when the module is already booted and operational. Doing so will lead to the module resetting or turning OFF.

Hi Vianney,

Thanks for your response. I think the pin which you’re referring to is RESET_IN_N, not POWER_ON_N. Page 42 of the document which you linked outlines the differences between these pins. We have the RESET_IN_N pin attached to another button on our carrier board and it works as per the documentation.

POWER_ON_N is related to RESET_IN_N in that it adjusts the behaviour of the module after the reset pulse is sent (whether the module turns off after reset pulse, or remains on). Our board design leaves the POWER_ON_N un-asserted, so when we assert RESET_IN_N the module forcefully turns off, as expected.

Could you please double check the document and confirm that I am understanding them correctly?

So far we have built 3 prototypes with the WP7610 modules and all 3 devices power off when asserting the POWER_ON_N pin after boot. Our 20 WP7609 prototype devices which use the same carrier board don’t exhibit this behaviour.

Hi @ben,
The behavior that you have observed is actually intended for WP7610. You could refer to page 92 for detailed information.

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Hi Vianney,

Thanks for clarifying. WP7610 is a Group B variant module which changes the POWER_ON_N pin behaviour.

Footnote a in the table you attached currently reads “When using Group A variants, this pin must not be toggled…”, should this actually refer to Group B? Another row in the table showing the outcome of the POWER_ON_N pin being asserted twice would also make the behaviour clearer between the variants.

Hi @ben,
In this case, The footnote also applies to Group B.