[WP7702] Can't go in ULPM Mode


We are currently using MangOH Yellow cards with a WP7702 chip.

Some of our systems in the field have encountered a problem.
They no longer go into ULPM mode.


We use the latest image of the MangOH Yellow software provided by the MangOH website: 0.7.0

With a slight modification of the Mango firmware: Modification of the accelerometer driver
And modification of the Yocto: Modification of the curl package + addition of python library

Method to switch to ULPM mode:
We use a Legato application in C

Code :

//Réveil sur Timer
//Réveil sur ADC
if (le_ulpm_ShutDown() == LE_OK){
FILE *fp = popen(“echo -e 'at+cpsms=0\r\n’ > /dev/ttyAT”,“r”);

We have never encountered this problem in the office so far.
As the systems are currently in the field, I cannot provide more logs.

Has anyone encountered this problem before?


How is the reproducibility?
Not sure if there is same problem with at!powermode command.


Our system wakes up every 15 minutes. It retrieves some data from an external sensor and switches back to ULPM mode. And every hour, it sends a file with the data by FTP. The system has been in the field for a month and has had no issues until this week.

We’ve restarted some systems at the office in hopes of reproducing the error, but this is an issue we hadn’t previously detected in our testing.