AXEL ULite and SBC Lynx Embedded Linux Kit (XUELK)

Info Box Applies to SBC Lynx

Introduction

SBC Lynx

SBC Lynx Embedded Linux Kit (XUELK for short) provides all the necessary components required to set up the developing environment to:

• build the bootloader (U-Boot)
• build and run Linux operating system on SBC Lynx board
• build and debug applications that will be executed on top of Yocto-based Linux distribution running on the target.

The main kit components are:

• hardware platform composed
• development host released in the form of Managed Virtual Machine, tailored for Yocto-based distribution
• technical documentation such hardware manuals, mechanical drawings, reference schematics, application notes etc.

The documents related to the software issues help the user to quickly start configuring the bootloader and the operating system, by hiding most of the complexity of the underlying hardware. Reading of the Managed Virtual Machine documentation is strongly recommended, as it plays a major role in the XUELK organization.

For more details about SBC Lynx hardware characteristics, please refer to the SBC Lynx Hardware Manual. An account for the reserved area of DAVE Embedded Systems website is required to access the kit contents.

Kit Contents

Component	Description	Notes
	SBC Lynx CPU: NXP i.MX6UL SDRAM: 512 GB DDR3 NOR: bootable SPI flash 32 MB NAND: 1GB	Please refer to SBC Lynx Hardware Manual
	AC/DC Single Output Wall Mount adapter Output: +12V – 2.0 A
	FTDI TTL/USB cable
	MicroSDHC card with SD adapter and USB adapter

XUELK software components

SBC Lynx Embedded Linux Kit is largely derived from the Yocto distributions released by NXP for the i.MX6 product family. For this reason most of the documentation provided by NXP remains valid for the XUELK development kit.

The following table reports the XUELK releases information.

	XUELK version
Release number	0.9.0
Release type	Major
Status	Beta
Release date	March 2016
Release notes	0.9.0
PCB version	CS214515
ConfigIDs (core/interfaces)	0x00000008/0x0000000E
MVM version	xuelk-0.9.0, tested with: Virtual Box 5.0.14 Vagrant 1.8.1
U-Boot version/release	U-Boot 2015.04/xuelk-0.9.0
Linux version/release	Linux 3.14.52/xuelk-0.9.0
Drivers	UART Ethernet SD/MMC USB Host USB Device NOR Flash NAND Flash ADC RTC
NXP BSP version	3.14.52_1.1.0_ga
Build System	Yocto Fido (1.8)

XUELK microSD Layout

The microSD provided with XUELK is used to store:

• A FAT32 partition (mmcblk0p1) containing:
  • U-Boot bootscript
  • Linux kernel and DTB binary images
  • XUELK documentation
  • XUELK virtual machine image in OFV format (MVM basic version)
• XUELK root file system partition (mmcblk0p2, ext3)

XUELK updates

It's recommended to use the latest available XUELK version. Please refer to Release notes for further information.

XUELK updating process consists of updating the Managed Virtual Machine it is based on. The procedure is described here.

Please note that this process implicitly updates source code repositories. Thus it is strongly recommended to create new local branches if you need to modify source code.

Release notes

After the XUELK DVDK installation, please check for updates of the source tree repositories provided with the kit, as described in XUELK Updates.

XUELK 0.9.0

Notes

First beta release.

Known issues and limitations

The following table reports the known limitations of this XUELK release:

Issue	Description
Rebooting in Linux may hang	Software reboot on Linux may hang (without rebooting the board) when root file system in on SD/MMC
USB OTG Current Limit	USB OTG current limit is set at 75mA in Host mode
LDO Mode not supported	LDO Mode is not supported in this SW release

Quick start guide

This chapter describes how to quickly start working with the XUELK kit. The following paragraphs will guide you through the setup and installation procedures.

Kit registration

Customers are recommended to register their kits. This allows them to get access to additional information and upgrades that are available in the download area of DAVE Embedded Systems web site.

Please register your development kit by sending an email to support-lynx@dave.eu, providing the kit P/N and CODE.

Host setup

As stated previously, XUELK is based on a Managed Virtual Machine. To install it, please follow the procedure described here.

In case you chose to use the Advanced version of the MVM, the project-name to be used is lynx.

Target setup

This section describes how to quick start an SBC Lynx board.

• connect a TTL/USB serial cable to J42 connector; J42 pinout is:
  • 1: TX data
  • 2: RX data
  • 3: 3.3V
  • 4: GND
• on host side start your favorite terminal that will be used to interact with the target's serial console; communication parameters are 115200-8-N-1
• optionally connect the system to Ethernet LAN by plugging cable into connector J16
• connect 12V power supply to J35 connector; J35 pinout is:
  • 1: GND
  • 2: VIN
• insert microSD card in the slot J43.

First boot

Once power has been applied to the target, U-Boot bootloader will be fetched from the SPI NOR flash and executed. Boot messages will be printed out on the serial console. Redundant U-Boot environment is stored in the NOR flash as well, as depicted in the following image.

NOR flash default partitioning

By default, U-Boot environment is configured to retrieve Linux kernel image stored in the microSD card. In turn, Linux kernel shall mount root file system from the mmcblk0p2 partition of the microSD card itself. At the end of boot process, Linux shell shall be available on the serial console.

The following dump shows the typical messages printed out during bootstrap process.

TBD

Target configuration for the development stage

During the development stage, the target is usually connected via Ethernet LAN to host machine and is configured to:

• retrieve binary images (i.e. Linux kernel) via TFTP protocol
• mount the development root file system via NFS protocol. This root file system is physically in the file system of the host machine as depicted here.

In DAVE Embedded Systems development kits, this configuration is generally denoted as net_nfs. The U-Boot environment variables affecting this configuration are detailed here.

For more details about TFTP and NFS servers on host side, plese refer to this page.

Advanced topics

Debugging with Eclipse

Please refer to this page.