SparkFun OpenLog Artemis


I recently acquired a SparkFun OpenLog Artemis board (without IMU) and have encountered an issue. While I am able to successfully log data at lower speeds, I am facing difficulties when attempting to log data at higher frequencies. I would greatly appreciate your assistance in finding a solution to this issue.

Thank you in advance.

++ MbedOS Error Info ++
Error Status: 0x80FF0144 Code: 324 Module: 255
Error Message: Assertion failed: handle != NULL
Location: 0x49DBD
File: mbed-os/targets/TARGET_Ambiq_Micro/TARGET_Apollo3/device/serial_api.c+411
Error Value: 0x0
Current Thread: main Id: 0x10007E4C Entry: 0x4AF11 StackSize: 0x1000 StackMem: 0x10006E28 SP: 0x1005FEEC
For more info, visit:
– MbedOS Error Info –

Huh, this certainly looks like a bug in the Mbed OS serial HAL for this chip. First thing’s first, what version of Mbed was this firmware built from? In mainline Mbed OS the assertion in that file is not on line 411, so this must be some sort of fork or branch.


Currently, I am utilizing an STM32F207ZG microcontroller to transmit data to an Artemis data logger through UART at a baud rate of 115200. While logging data at a low frequency of 1Hz, everything functions correctly. However, when attempting higher frequencies, I encounter issues. I appreciate your prompt response and thank you in advance for any assistance.

But like, where did you get the firmware running on the OpenLog Artemis?

I have acquired the Artemis device, and currently, I have only uploaded firmware to the STM32CubeIDE. It appears that the Artemis already comes with pre-existing code. Should I also run firmware on the Artemis device? If so, could you please provide guidance on the necessary steps for the firmware setup?

Thank you in advance for your prompt response.

Does SparkFun have any instructions for building and installing the firmware? You’d have to refer to those. Also, just to confirm, this stacktrace is coming from the OpenLog, right, not the STM32F207?

Yes, the provided stack trace is originating from the OpenLog. While there are steps available for installing OpenLog firmware, it’s worth noting that OpenLog typically comes with pre-installed firmware.

Steps for Firmware installation:

Thank you in advance for your prompt response.

That’s the steps for firmware upload, but where’s the firmware that’s installed come from?

I haven’t installed any firmware; Artemis came with preinstalled firmware, specifically the Binaries/OpenLog_Artemis-V10-v18.bin.

It looks like there is a much newer version available: OpenLog_Artemis/Binaries/OpenLog_Artemis-V10-v25.bin at main · sparkfun/OpenLog_Artemis · GitHub