Hi. I am currently evaluating the STEVAL-ASTRA1B as a low-power LoRaWAN-GPS tracker. My goal is to have the device wake up every 10 minutes to send a GPS position.
I am however facing some problems getting the current consumption down to the advertised uA levels mentioned in UM3019.
Before BTN2 is pressed, I measure 3.2uA. However, when I follow the STANDBY_RTC example for the WB55 (https://github.com/STMicroelectronics/STM32CubeWB/tree/master/Projects/P-NUCLEO-WB55.Nucleo/Examples/PWR/PWR_STANDBY_RTC), I am not able to get it lower than 2.2mA after BTN2 has been pressed once. I have also tried the stm32_lpm_if.c PWR_EnterStopMode() functions, and get the same results. I have also tried disabling VREG1 and VREG2 to disable peripherals, and disabled debug in low power mode.
UM3019 tells me that "In the STEVAL-ASTRA1B, the current consumption in low power is optimized by removing SB943.". However, I am unable to locate it on my board. I also guess it would disable the BTN2 as a wakeup source, as the schematics show it as a short between the button and WAKEUP.
What am I missing in order to achieve uA levels in STOP or STANDBY modes?
Is there any example code available for the board to achieve this? In case FP-ATR-ASTRA1 performs this, what settings should be used?
Is there any action needed to get the STM32WL55 to a low power mode?
