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Technexion i.MX8M Pico board
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This file documents the Buildroot support for the Technexion i.MX8M
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Pico board. The Pico i.MX8M system-on-module [1] is present in
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development kits like the Pico Pi i.MX8M [2].
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Build
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=====
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First, configure Buildroot for the i.MX8M Pico board:
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make imx8mpico_defconfig
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Build all components:
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make
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You will find in output/images/ the following files:
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- bl31.bin
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- boot.vfat
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- Image
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- imx8-boot-sd.bin
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- lpddr4_pmu_train_fw.bin
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- pico-8m-dcss-ili9881c.dtb
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- pico-8m.dtb
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- rootfs.ext4
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- sdcard.img
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- signed_hdmi_imx8m.bin
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- u-boot.imx
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Flashing sdcard.img on the eMMC
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===============================
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i.MX8M Pico board does not have a SD card slot. The storage is an
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eMMC. An easy way to flash the eMMC is to use the u-boot ums
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command. The boards are sold pre-flashed with such a u-boot. It is
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assumed here that the board has already a working u-boot on eMMC and
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jumpers are set to boot on eMMC. See [3].
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Jumper configuration for eMMC boot:
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J1: jumper on pins 4 and 6.
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J2: jumper on pins 2 and 4.
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In case the board was flashed with a wrong u-boot, or the eMMC is
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erased, u-boot can be loaded by USB Serial Download boot mode, using
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imx-usb-loader. See [3] and [4].
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For flashing:
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- Plug the micro USB cable from the Debug USB Port, to your computer
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- Plug the USB Type C to your computer, this will power up the board
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In the U-Boot prompt launch:
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=> ums 0 mmc 0
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This will mount the eMMC content in the host PC as a mass storage device.
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To determine the device associated to the eMMC card have a look in the
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/proc/partitions file:
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cat /proc/partitions
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If your system automatically mount some device partitions, make sure
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to unmount them.
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Buildroot prepares a bootable "sdcard.img" image in the output/images/
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directory, ready to be dumped on the eMMC. Launch the following
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command as root:
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dd if=output/images/sdcard.img of=/dev/<your-sd-device>
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*** WARNING! This will destroy all the eMMC content. Use with care! ***
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This operation can take several minutes, depending on the image
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size. When tested, a 2MB/s transfer rate was observed.
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For details about the medium image layout, see the definition in
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board/freescale/common/imx/genimage.cfg.template.
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Boot the i.MX8M Pico board
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==========================
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To boot your newly created system:
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- put a micro USB cable into the Debug USB Port and connect using a terminal
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emulator at 115200 bps, 8n1;
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- power on the board, with USB Type C connector.
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Enjoy!
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[1]. https://www.technexion.com/products/system-on-modules/pico/pico-compute-modules/detail/PICO-IMX8M
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[2]. https://www.technexion.com/products/system-on-modules/pico-evaluation-kits/detail/PICO-PI-IMX8M-BASIC
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[3]. https://www.technexion.com/support/knowledgebase/boot-configuration-settings-for-pico-baseboards/
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[4]. https://www.technexion.com/support/knowledgebase/loading-bootable-software-images-onto-the-emmc-of-picosom-on-pico-pi/
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