XIAO_BLE_Sense(mbed 2.7.2) battery charge and voltage monitor, analogRead(P0_31) does not work

Products & Technology XIAO
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I also tried with BSP2.9.1+patch, but it does not seem to be able to maintain Sleep mode.
bsp291+patch.zip (1.6 MB)

edit
Sorry, I was checking with XIAO non Sense.
With BSP2.9.2, BSP2.9.1+patch, I confirmed that it cannot maintain sleep mode and wakes up after about 5 seconds.
BSP2.9.1(no patch) is good, but can’t read voltage.