I am working on a data logger that requires measurements to be taken during narrow time windows. I have been storing this Data on SD cards however the write times are very inconsistent. Usually a few ms for 1 kB but occasionally over 100ms which blocks the timing critical measurements.

I am using an STM32L4 microcontroller, FreeRTOS and SDIO configured with DMA. I had hoped that this would allow long writes to yield to more timing critical tasks however STM32 SDIO implementation does not seem to like being interrupted.

What other mass storage options are viable that have consistent write times?

I am working on a data logger that requires measurements to be taken during narrow time windows. I have been storing the measurement data on SD cards, however, the write times are very inconsistent, usually a few ms for 1kB but occasionally over 100ms which blocks the timing critical measurements.

I am using an STM32L4 microcontroller, FreeRTOS, and SDIO configured with DMA. I had hoped that this would allow long writes to yield to more timing critical tasks however STM32 SDIO implementation does not seem to like being interrupted.

What other mass storage options are viable that have consistent write times?