Getting Started with FRDM-IMX91S

The i.MX Linux board support package (BSP) is a collection of binary files, source code and support files that are used to boot an Embedded Linux image on a specific i.MX development platform.

Current releases of Linux binary demo files can be found on the Linux download page. Additional documentation is available in the i.MX Linux documentation bundle under the Linux sections of the i.MX Software and Development Tools.

2.1 Overview

FRDM-IMX91S support booting from NAND and SD card.

This Getting Started guide only outlines a few methods of flashing the Linux BSP image to an SD card. Experienced Linux developers can explore other options if desired.

2.2 Download NXP Linux BSP Pre-Built Image

The latest prebuilt images for the FRDM-IMX91S are available on the FRDM i.MX 91S Development Board.

The prebuilt NXP Linux binary demo image provides a typical system and basic set of features for using and evaluating the processor. Without modifying the system, the users can evaluate hardware interfaces, test SoC features and run user space applications.

2.3 Burn NXP Linux BSP Image Using Universal Update Utility (UUU)

In addition to the connections from "Out of the Box" section, connect the USB1 (J5) to the host machine using the proper USB cable.

Turn off the board. Refer to the 1.4 Boot Switch Setup section and configure the board to boot in serial download protocol (SDP) mode.

Depending on the OS used in the host machine, the way to transfer the Linux BSP image onto an SD card can vary. Choose an option below for detailed instructions:

$ chmod a+x uuu
$ sudo ./uuu -b sd_all imx-image-full-imx91frdmimx91s.rootfs.wic.zst

 uuu.exe -b sd_all imx-image-full-imx91frdmimx91s.rootfs.wic.zst

In this section, a brief guide of how to build Yocto BSP image for FRDM-IMX91S is introduced, along with how to add Matter support and how to build Debian release image.

3.1 FRDM-IMX91S Yocto BSP

The FRDM-IMX91S BSP release is based on i.MX SW 2024 Q3 release with Yocto Project 5.0 (Scarthgap). To build FRDM-IMX91S image from source code, please first check i.MX Yocto Project User’s Guide to get familiar with Yocto project and Yocto build. Then please follow the below steps to build image for FRDM-IMX91S.

1. Download i.MX SW 2024 Q3 BSP Release:

$ repo init -u https://github.com/nxp-imx/imx-manifest -b imx-linux-scarthgap -m imx-6.6.36-2.1.0.xml 
$ repo sync

2. Integrate FRDM-IMX91S layer into Yocto code base:

$ cd ${MY_YOCTO}/sources
$ git clone https://github.com/nxp-imx-support/meta-imx-frdm.git

3. Yocto Project Setup:

$ cd ${MY_YOCTO}
$ MACHINE=imx91frdmimx91s DISTRO=fsl-imx-xwayland source sources/meta-imx-frdm/tools/imx-frdm-setup.sh -b frdm-imx91s

4. Build images:

$ bitbake imx-image-full

5. Flashing SD card image:

$ zstdcat imx-image-full-imx91frdmimx91s.rootfs.wic.zst | sudo dd of=/dev/sdx bs=1M && sync

Or using uuu to burn image into SD card:

$ uuu -b sd_all imx-image-full-imx91frdmimx91s.rootfs.wic.zst

6. Change boot switch SW1[4:1] to “0011” to select SD card boot, insert the SD card and power up the FRDM-IMX91S board

3.2 FRDM-IMX91S Matter Support

FRDM-IMX91S has support for Matter. To include Matter support, please follow below steps to include Matter layer into Yocto build.

1. Download i.MX SW 2024 Q3 BSP Release:

$ repo init -u https://github.com/nxp-imx/imx-manifest -b imx-linux-scarthgap -m imx-6.6.36-2.1.0.xml
$ repo sync

2. Download i.MX Matter Yocto layer:

$ cd ${MY_YOCTO}/sources/meta-nxp-connectivity
$ git remote update
$ git checkout imx_matter_2024_q3

3. Integrate FRDM-IMX91S layer into Yocto code base:

$ cd ${MY_YOCTO}/sources
$ git clone https://github.com/nxp-imx-support/meta-imx-frdm.git

4. Yocto Project Setup:

$ cd ${MY_YOCTO}
$ MACHINE=imx91frdmimx91s-iwxxx-matter DISTRO=fsl-imx-xwayland source sources/meta-imx-frdm/tools/imx-frdm-matter-setup.sh bld-xwayland-frdmimx91s

5. Build images:

$ bitbake imx-image-multimedia

3.3 FRDM-IMX91S Debian

FRDM-IMX91S has support for Debian 12 OS. i.MX Debian Linux SDK distribution is a combination of NXP-provided kernel and boot loaders with a Debian distro user-space image, which includes:

• Debian-based rootfs;
  1. Debian Base (basic packages)
  2. Debian Server (more packages without GUI Desktop)
  3. Debian Desktop (with GNOME GUI Desktop)
• Linux kernel
• BSP components
• Various applications (graphics, multimedia, networking, connectivity, security and AI/ML)

For more details of the NXP Debian Linux SDK Distribution, please check the NXP Debian Linux SDK Distribution for i.MX and Layerscape page.

Quick Start with Debian

To create an SD card with Debian for FRDM-IMX91S, please follow below steps.

1. Download flex-installer on the Linux host:

$ wget http://www.nxp.com/lgfiles/sdk/lsdk2412/flex-installer
$ chmod +x flex-installer
$ sudo mv flex-installer /usr/bin

2. Plug the SD card into the Linux host and install the images as below:

# format SD card
$ flex-installer -i pf -d /dev/sdb
# automatically download and install images into SD card
$ flex-installer -i auto -d /dev/mmcblk1 -m imx91frdmimx91s

3. Plug the SD card into the FRDM-IMX91S board and install the extra packages as below:
1. Setup Ethernet network interface by DHCP or setting it manually

$ dhclient -i end0

2. Set correct system time, for example:

$ date -s "22 Nov 2024 09:00:00"

3. Install extra packages for GNOME GUI Desktop version:

$ debian-post-install-pkg desktop

4. Or install extra packages for Server version without GUI Desktop:

$ debian-post-install-pkg server

5. After finishing the installation, run the reboot command to boot up the Debian Desktop/Server system

Building Debian Images with Flexbuild

To build Debian image with Flexbuild for FRDM-IMX91S, please follow the below steps.

1. Set up the build environment:

$ git clone https://github.com/nxp/flexbuild
$ cd flexbuild && ./setup.env
#Continue to run commands below in case you need to build in Docker due to lack of Ubuntu 22.04 or Debian 12 host
$ bld docker
$ source setup.env

2. Build image with Flexbuild:

$ bld -m imx91frdmimx91s

3. Flexbuild usage:
To build individual part of the image, please check below command list for Flexbuild usage:

$ bld uboot -m imx91frdmimx91s (compile u-boot image for imx91frdmimx91s)
$ bld linux (compile linux kernel for all arm64 i.MX machines)
$ bld bsp -m imx91frdmimx91s (generate BSP firmware)
$ bld boot (generate boot partition tarball including kernel, dtb, modules, distro bootscript for iMX machines)
$ bld multimedia (build multimedia components for i.MX platforms)
$ bld rfs -r debian:server (generate Debian server rootfs)
$ bld apps -r debian:server (compile apps against runtime dependencies of Debian server RootFS)
$ bld merge-apps -r debian:server (merge iMX-specific apps into target Debian server RootFS)
$ bld packrfs -r debian:server (pack and compress target debian server rootfs)

To enable faster development for users of all skill levels, NXP provides extensive example applications to showcase various features and capabilities of the platform.

4.1 Application Code Hub

The Application Code Hub  (ACH) repository enables engineers to easily find microcontroller and processor software examples, code snippets, application software packs and demos developed by NXP in-house experts. This space provides a quick, easy and consistent way to find microcontroller and processor applications.

ACH provides filter and search options to quickly find specific applications. With the support of Git capabilities, there is an easy way to import and use applications within user’s development environments.

To learn more details of ACH, please visit this link.

4.2 GoPoint for i.MX Applications Processors

The GoPoint for i.MX Application Processors is a user-friendly application launches prebuilt applications packed with the Linux BSP, giving users an excellent out of the box experience and hands on experience with i.MX SoC's capabilities. GoPoint highlights advanced features while providing practical solutions for implementation, with source code and build recipes for the applications provided in GitHub .

To learn more details of GoPoint, please visit this link.

Debug Terminal in Linux

Serial Communication Console Setup

The serial-to-USB drivers are available at CH342F Linux Drivers .

On the command prompt of the Linux host machine, run the following command to determine the port number:

$ ls /dev/ttyCH343USB*

The first number is for Arm® Cortex®-A53.

Minicom

Use the following commands to install and run the Minicom program:

1. Install Minicom using the Ubuntu package manager

$ sudo apt-get install minicom

2. Launch Minicom using a console window using the port number determined earlier

$ sudo minicom /dev/ttyCH343USB * -s

Configure Minicom as shown in Figure and Exit configure.

Debug Terminal in Windows

Security and Integrity

System security and integrity are always one of the most critical aspects to be considered in product development.

FRDM-IMX91S support secure boot feature and encrypted boot feature, helping to prevent unauthorized software execution during the device boot sequence and protect bootloader data from unauthorized access.

For more details of the secure boot feature, please check application note AN12312 Secure Boot on AHAB Supported Devices.

For more details of the encrypted boot feature, please check application note AN13994 i.MX Encrypted Boot on AHAB-Enabled Devices.

Fast Boot

In certain use cases, there is a requirement for the device boot time, which means the device needs to complete booting in a given time limit.

To optimize the boot time, FRDM-IMX91S supports falcon mode in U-Boot. Falcon mode is a feature in U-Boot that enables fast booting by allowing SPL to directly start the Linux kernel. It completely skips the U-Boot loading and initialization, with the effect of reducing the time spent in the bootloader.

For how to enable falcon mode and further optimize boot time, please check AN14093 Fast Boot on i.MX 8M and i.MX 9 Using Falcon Mode and Kernel Optimizations.

NAND Boot

FRDM-IMX91S has a 256MB NAND flash memory on the board. Since the rootfs of a full functionality usually takes over 5GB, the rootfs that can fit into the 256MB NAND storage have to be customized. For how to compile the bootloader and rootfs for NAND boot, and how to download the image into the NAND, please refer to the i.MX FRDM Software User Guide.

Board Information

• FRDM-IMX91S Design Files
• FRDM-IMX91S Schematics

Communities

• FRDM-IMX91S Community Trainings