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Need a hand on a small project with Maaxboard RT

samr2

Good Day,

I would like an expert to give me a hand developing a small Bare-Metal R&D project with following definitions (We will agree and I'll pay for that):

I need to have a SPI 24 bits ADC and a Small SPI touch display (ILI9341 Controller Chip for example or equivalent) connected to and controlled by a MaaxboardRT (only through CM4).

CM4 should be able to receive analog input from external ADC and take care of display simultaneously.

The project has to be developed in MCUXpresso and defined as a Multicore Project.

The result of this project will be a MCUXpresso multicore project code and a wiring diagram up and running.

Please let me know if you are interested and how much it will cost you doing that or any other questions you may have.

Thanks in advance,


Cheers,



  

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  • 0

    Hi samr2,

    I have the SPI master on MaaXBoard-RT, J1 header, working:

    tjaekel/MaaXBoard-RT_lpspi_edma_b2b_transfer_master_cm7: MaaXBoard-RT LPSPI4 demo (github.com)

    or see this thread:

     MaaXBoard-RT: LPSPI4 and GPIO INT for you 

    BTW:
    you have mentioned, you need TWO (independent) SPI interfaces: one for your own display, one for the ADC.

    I see just one SPI on J1 header (as LPSPI4):
    OK, you could use a "shared SPI bus" - the same bus with TWO SPI_CS0 and SPI_CS1 signals.
    But it will have a negative side effect:
    When you update your LCD (GUI) via SPI - you cannot drain sampling results from ADC (SPI is busy).
    An update on LCD via SPI can take a long time (e.g. writing a new background BMP via SPI).
    During this period you cannot handle ADC, not able to drain results.
    And if your SPI LCD needs a slower SPI clock speed - it slows down also the speed for reading ADC.

    This would result in a "jitter" for your sampling clock: it is not anymore quite accurate as "ever X micro-sec get results from ADC".
    The period X will "jitter" a lot (sometimes too late because the SPI is busy with LCD).

    Option:
    You could change to an ADC with SAI (I2S) interface (as a regular audio ADC would be).
    The SAI3 would be free (and independent of SPI, used for LCD).

  • 0 in reply to tjaekel

    Hi samr2,

    if you want to start playing with your SPI based ADC and LCD display,
    I have my project framework up and running:

    tjaekel/MaaXBoard-RT_SPIder: MaaXBoard-RT SPIder framework (github.com)

    You can connect your ADC (or LCD display) on the extension header J1, as SPI, and
    fire SPI transactions from UART command line:
    send any sequence of bytes via SPI to a slave, see "help" and "rawspi"

    I am thinking to add a command to send also words, as "spitr" command, e.g. 16bit or 32bit words over SPI.

    Have fun...

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