{"id":19973,"date":"2025-12-15T11:13:41","date_gmt":"2025-12-15T03:13:41","guid":{"rendered":"https:\/\/icop-shop.com\/?p=19973"},"modified":"2026-01-05T17:46:31","modified_gmt":"2026-01-05T09:46:31","slug":"technical-tips-how-to-test-the-spi-bus-on-nx8mm-35","status":"publish","type":"post","link":"https:\/\/icop-shop.com\/ja\/technical-tips\/technical-tips-how-to-test-the-spi-bus-on-nx8mm-35\/","title":{"rendered":"[Technical tips] How to test the SPI bus on NX8MM-35"},"content":{"rendered":"
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This article will tell you how to test the SPI bus on the NX8MM-35 in Yocto Linux.
\nThe SPI bus is an optional feature supported on ICOP’s\u00a0NX8MM-35<\/a>, and it shares functionality with UART3 on the board.
\nIn the tips below, we will provide the guide step by step.<\/p>\n

\n<\/div>\n<\/div>\n
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Tools you need:<\/h2>\n
    \n
  1. NX8MM-35 (Find it\u00a0here<\/a>)<\/li>\n
  2. Yocto Linux 4.0:Image<\/a>\u00a0\/\u00a0Guide<\/a><\/li>\n
  3. USB to micro USB cable for restoring image.<\/li>\n
  4. SPI Testing file (Put it in a USB disk):\u00a0link<\/a><\/li>\n
  5. A testing wire to test SPI bus self-transmitting.
    \n\"\"<\/li>\n
  6. Soldering iron for switching UART3 function to SPI bus.<\/li>\n<\/ol>\n

    Switching the UART3 to SPI bus on NX8MM-35.<\/h2>\n

    On NX8MM-35, the UART3 and SPI bus can be switched by modifying the resistor on the board.
    \nPlease follow the image below and use the soldering iron to move the 0 ohm resistor to the correct location.<\/p>\n

    \"developer-mode\"<\/p>\n

    Test the SPI function in Yocto Linux.<\/h2>\n

    \"\"<\/p>\n

     .\/spidev_test -D \/dev\/spidev3.0 -v -p xxx<\/pre>\n
    In this case, we type .\/spidev_test -D \/dev\/spidev3.0 -v -p SPITESTING, and if the test succeed, it will show the “SPITESTING” in the test result.<\/p>\n
      \n
    1. Plug testing wire to the J12 (SPI bus) on NX8MM-35.<\/li>\n
    2. Plug the USB disk with SPI testing application in the NX8MM-35 and turn it on; then open the terminal in Yocto Linux.<\/li>\n
    3. Mount the USB to Lunix and access the USB file.<\/li>\n
    4. Run below command in the USB file:<\/li>\n<\/ol>\n
      For the steps above, you could find all of the information in the image below:<\/p>\n
      \"developer-mode\"<\/p>\n
      Check the video:<\/h2>\n
      <\/div>\n
      \n<\/div>\n<\/div>\n
      \n
      \"NX8MM-35\"<\/a><\/div>\n
      \n
      \n
      Main features of\u00a0NX8MM-35<\/a>:<\/h3>\n