nRF52840 Data Storage Issues and Recommendations

[Andy73650]

I would like to seek some assistance. My sensor generates 27.2 KBytes of data per second. I initially intended to use the "w25n01gvzeig" for storage, but I discovered that the QSPI in the SDK does not support NAND flash, so I had to abandon its usage. Instead, I used the SDK's QSPI example to operate the MX25R6435F NOR flash on the nrf52840-DK board. However, I found that writing 256 bytes took 1.110 seconds to complete, which is much slower than what I require.

I have the following questions to ask:

1. Can the MX25R6435F achieve my requirements at its fastest when using QSPI?
2. If I use an SD card, will the speed be limited by the SPI interface as well, preventing me from meeting my needs?
3. Are there other storage options more suitable for my situation?

Thank you for your help in advance.

[Sigurd]

Hi,

256 bytes in 1.110 second sounds very low. What sample did you use? How did you measure the speed?

[Andy73650]

Thank you for your response. As a beginner, I'm not sure if my calculation method is correct. I used the QSPI example from the SDK and attempted to write 256 bytes of data. I sent data to the computer both at the beginning and the end of the write process, and observed a time difference of 1.110 seconds between the two data transmissions.

[Sigurd]

Hi,

I have done some testing on the https://infocenter.nordicsemi.com/topic/sdk_nrf5_v17.1.0/usbd_msc_example.html example in the past, and have gotten around 60kb/s write speed. See this post Write speed with MX25R6435F on nrf52840dk 

[Andy73650]

It seems that I have made a mistake in my settings. I will continue trying the QSPI example. Also, I would like to ask if using an SD card could be a better solution to handle my issue?

[Sigurd]

Andy73650 said:

Also, I would like to ask if using an SD card could be a better solution to handle my issue?

Yes, that should work fine. The nRF52840 have a High-speed 32 MHz SPI peripheral instance you can use.