Logging into ram

edited December 2018 in Firmware

Good afternoon,

I would like to collect hi speed data from accelerometer and gyro (as fast as possible). As I read the documentation when metamotion logging, it saves the data into the rom. Max logging capacity of the device can hold only 5 seconds of 800hz data.
I would like to use 200-300 times a day, and the nand cells max write cycles are not so big. Around 3000-5000 in avarage before they will die. So after 2-3 weeks the device/rom could be broken.
Is there a possibility to use the ram only when logging and transfer the result immediately onto the phone?
I am writing my app in C#, UWP.

Comments

  • @Teddybee said:
    Good afternoon,

    I would like to collect hi speed data from accelerometer and gyro (as fast as possible). As I read the documentation when metamotion logging, it saves the data into the rom. Max logging capacity of the device can hold only 5 seconds of 800hz data.
    I would like to use 200-300 times a day, and the nand cells max write cycles are not so big. Around 3000-5000 in avarage before they will die. So after 2-3 weeks the device/rom could be broken.

    What board are you using? Current generation boards use 8MB NOR flash chips for external memory.

    Is there a possibility to use the ram only when logging and transfer the result immediately onto the phone?

    You've basically described streaming, which ultimately doesn't work because the ble adapter doesn't stream data that fast.

  • edited December 2018

    Hello Eric,

    I am using Metamotion C.
    I have read on the page:
    "Record raw sensor data via Bluetooth at up to 400Hz. Stream raw sensor data at up to 100Hz."
    A assume the record this case is a log to NOR flash.
    nRF52 M4F has two variants, 64/32 kB RAM or 256 kB RAM.
    800hz*40byte data for 4 seconds take only 128kbyte of ram.

    P.S.: I have read about a nor flash. It can do around 100,000 Program-Erase cycles.

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