126 lines
5.1 KiB
ReStructuredText
126 lines
5.1 KiB
ReStructuredText
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.. _mimxrt_intro:
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Getting started with MicroPython on the i.MXRT
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==============================================
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Using MicroPython is a great way to get the most of your i.MXRT board. And
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vice versa, the i.MXRT chip is a great platform for using MicroPython. This
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tutorial will guide you through setting up MicroPython, getting a prompt, using
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the hardware peripherals, and controlling some external components.
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Let's get started!
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Requirements
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------------
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The first thing you need is a board with an i.MXRT chip. The MicroPython
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software supports the i.MXRT chip itself and any board should work. The main
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characteristic of a board is how the GPIO pins are connected to the outside
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world, and whether it includes a built-in USB-serial converter to make the
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UART available to your PC.
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Names of pins will be given in this tutorial using the chip names (eg GPIO2)
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and it should be straightforward to find which pin this corresponds to on your
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particular board.
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Powering the board
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------------------
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If your board has a USB connector on it then most likely it is powered through
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this when connected to your PC. Otherwise you will need to power it directly.
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Please refer to the documentation for your board for further details.
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Getting the firmware
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--------------------
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Firmware versions are provided at the
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`MicroPython download page <https://micropython.org/download/?port=mimxrt>`_.
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You can download the most recent MicroPython firmware .hex or .bin file to load
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onto your i.MXRT device. From that download page you have two main choices:
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* stable firmware builds
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* daily firmware builds
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If you are just starting with MicroPython, the best bet is to go for the stable
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firmware builds. If you are an advanced, experienced MicroPython i.MXRT user
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who would like to follow development closely and help with testing new
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features, there are daily builds.
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Deploying the firmware
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----------------------
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Once you have the MicroPython firmware you need to load it onto your
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i.MXRT device. The exact procedure for these steps is highly dependent
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on the particular board and you will need to refer to its documentation
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for details.
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Teensy 4.0 and 4.1
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~~~~~~~~~~~~~~~~~~
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For Teensy 4.0 and 4.1 you have to use the built-in loader together with the PC
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loader provided by PJRC. The built-in loader will be activated by pushing the
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button on the board. Then you can upload the firmware with the command::
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teensy_loader_cli --mcu=imxrt1062 -v -w firmware.hex
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IMXRT10xx-EVK boards
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~~~~~~~~~~~~~~~~~~~~
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The IMXRT10xx-EVK boards have a second USB port connected to a support MCU.
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Connecting that USB port to your PC will register a disk drive with the name of
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the board. Just copy the firmware.bin file to this drive, and that will start
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the flashing procedure. You will know that the flash was complete, if that
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drive disappears and reappears. If you decided to install the very useful
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Segger open-SDA firmware on that sidekick MCU, then you have to use the debugger
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software to upload the i.MXRT firmware.
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Seed ARCH MIX board
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~~~~~~~~~~~~~~~~~~~
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Firmware upload to the Seed ARCH MIX board is less convenient. The vendor
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suggests using J-Link as a method and tool. For that, follow the instructions
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given by Seed in their Wiki at
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https://wiki.seeedstudio.com/Arch_Mix/#flashing-arduino-bootloader-to-arch-mix.
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You will need a J-Link debug probe and software. You may find Segger JLink edu
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or Segger JLink edu mini convenient. As a matching loader you can use
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JFlashLite. The target address for loading is 0x60000000.
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The MIMXRT family also support a serial upload method. The software for serial
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upload is provided by NXP. The steps to use it are:
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- Connect J3, Pin 19 to 3.3V (GPIO_AD_B0_05).
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- Change the DIP-Switch settings from off-off-on-off to off-off-off-on
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- Push Reset
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- Run the upload with: ./FLASH.sh <firmware_image_file name>
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- Once the upload has finished, set the DIP-switch back to off-off-on-off.
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- Remove the Jumper to J3, Pin19 and push reset
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To avoid running the Flash loader as superuser, you can copy the provided udev-rules
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script to /etc/udev/rules.d/. FLASH.sh calls two binaries, blhost and sdphost,
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which are provided by NXP under the BSD-3-Clause License. A version of these
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binaries and the script can be downloaded at
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https://github.com/robert-hh/Shared-Stuff/blob/master/mimxrt_serial_downloader.zip.
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Serial downloading can be used for the NXP MIMXRT boards as well. But the built-in loader
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is much more convenient to use.
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Serial prompt
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-------------
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Once you have the firmware on the device you can access the REPL (Python prompt)
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over USB.
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From there you can follow the i.MXRT tutorial.
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Troubleshooting installation problems
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-------------------------------------
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If you experience problems during flashing or with running firmware immediately
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after it, here are some troubleshooting recommendations:
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* Be aware of and try to exclude hardware problems. There are two common
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problems: bad power source quality, and worn-out/defective Flash ROM.
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Speaking of power source, not just raw amperage is important, but also low
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ripple and noise/EMI in general. The most reliable and convenient power
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source is a USB port.
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