read accelerometer data

Good question. Ability to stream all the the SDK data including temperature, analogous to the ARM/EVB would have been valuable. However with focus on a cube demo it seems that only one sensor can be logged at a time.

A modfied SDK5.1 python client may be reasonable in your narrow case because it appears that quaternion data packet is alternately sourced with your selected data packet (accelerometer in your case) by the MSP430 on the serial BT stream. Some edits to eMPL-client.py may enable you to alternately write quaternion and accelerometer data to the same log file and possibly at 50Hz for both. (Of course this not an embedded solution but may aid initial development and help finalize embedded (MCU) code requirements)

If you want to go further you may need to review the MSP430 "main.c" (MotionFit_With_eMPL511_Releasesimple_appsmsp430mllite_test.c ??) to see how difficult it would be to modify the firmware and output multiple sensor data and ideally a time stamp and temperature data with one command. You will need full TI CCS and a flash programmer; there is supposed to be an CCS eclipse project in the 5.1 release and (Has anyone had success recently modifying SDK firmware? The MotionDriver_Tutorial12212018CB.pdf is a bit confusing on the current mechanics of firmware update.)

Perhaps sectionbest can confirm/correct this understanding. Do the instructions in this post https://invensense.tdk.com/developers/forum/viewtopic.php?p=3113#p3113 also relate to modifying the wireless SDK5.1 ? The "main.c" in this folder is motion_driver_test.c

Please keep us posted on how you finally resolve this interesting problem :)

Thank you Vortex for that thoughtful response. The accel data one can get at a lower rate then quaternion with our current API is the command INVA.