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Connecting 2 micro controlers at high speed

Discussion in 'Microcontrollers, Programming and IoT' started by rhubarbdog, Mar 22, 2019.

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  1. rhubarbdog


    May 15, 2018
    I have 2 pyboards ARM smt32.
    I have linked them successfully over uart at 1152000 baud. But as i increase the baud the transfer time suddenly goes up to milli seconds from micro seconds. A post on another site mentions differential line drivers.
    I can locate plenty of products but don't have any knowledge
    How do i wire one between Tx on one uart and Rx on the other. I only need to send data?
    Can anyone advise a part or series preferably in throuh the hole solderable packages. DIP would be ideal then i could build on breadboard.
    This post says it uses 20Mbit differential line drivers and acheives a baud of 3Mbit. When I've looked at some texas instruments pdfs none have described themselves in such a way.

    Thanks for any help
  2. hevans1944

    hevans1944 Hop - AC8NS

    Jun 21, 2012
    You might want to visit this page and read the comments therein. Or maybe forego the UART approach entirely and bang on the GPIO bits with some well-crafted assembly code. Some help with that might be available here. An asynchronous data transfer protocol, which is what a UART implements, between closely-paired processors seems inefficient and unnecessary IMO. Perhaps you should consider a clocked, synchronous, protocol such as I2S when transferring data at warp speeds between your microprocessors. Also, if using any sort of multi-tasking operating system on either or both microprocessors, bear in mind that "real time" response is difficult or impossible to achieve without a special kernel written to support pre-emptive multi-tasking with appropriately priortized hardware interrupt support.
  3. rhubarbdog


    May 15, 2018
    The thing i like about uart is it appears to have a buffer at a near hardware level. Probably using dma. This allows a bit of skack time so the reciever can write results to SD Card.
    It takes 1milli second to write a 4kb block. When measuring at 4kHz that's many missed results and i want to go faster.
    When I've tried with spi i was getting missing frames. I'm unable to buffer on the tranmitter side the micro controler is running flat out and i need little or no variance.
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