136 lines
3.4 KiB
Plaintext
136 lines
3.4 KiB
Plaintext
Lego Mindstorms EV3
|
|
|
|
Intro
|
|
=====
|
|
|
|
This is the buildroot basic board support for the Lego Mindstorms EV3
|
|
programmable brick. No support for sensors and drivers is provided for the
|
|
moment.
|
|
|
|
The Lego Mindstorms EV3 brick comprises a Texas Instruments AM1808 SoC, with
|
|
an ARM 926EJ-S main processor running at 300 MHz.
|
|
See:
|
|
- https://en.wikipedia.org/wiki/Lego_Mindstorms_EV3
|
|
- http://www.lego.com/en-us/mindstorms/products/ev3/31313-mindstorms-ev3/
|
|
- http://www.ti.com/product/am1808
|
|
|
|
The buildroot configuration uses the Linux kernel of the ev3dev project.
|
|
See:
|
|
- http://botbench.com/blog/2013/07/31/lego-mindstorms-ev3-source-code-available/
|
|
- https://github.com/mindboards/ev3sources
|
|
|
|
Note that the EV3 configuration uses gcc 4.7, as the boot is broken with gcc
|
|
4.8.
|
|
|
|
How it works
|
|
============
|
|
|
|
Boot process :
|
|
--------------
|
|
|
|
The u-boot on-board the EV3 brick has provision to boot a Linux kernel from the
|
|
external µSD card. It will try to load a uImage from the first µSD card
|
|
partition, which must be formatted with a FAT filesystem.
|
|
|
|
How to build it
|
|
===============
|
|
|
|
Configure Buildroot
|
|
-------------------
|
|
|
|
The lego_ev3_defconfig configuration provides basic support to boot on the Lego
|
|
Mindstorms EV3 programmable brick:
|
|
|
|
$ make lego_ev3_defconfig
|
|
|
|
Build everything
|
|
----------------
|
|
|
|
Note: you will need to have access to the network, since Buildroot will
|
|
download the packages' sources.
|
|
|
|
$ make
|
|
|
|
Result of the build
|
|
-------------------
|
|
|
|
After building, you should obtain this tree:
|
|
|
|
output/images/
|
|
├── rootfs.ext2
|
|
├── rootfs.ext3 -> rootfs.ext2
|
|
└── uImage
|
|
|
|
|
|
Prepare your SDcard
|
|
===================
|
|
|
|
The following µSD card layout is recommended:
|
|
|
|
- First partition formated with a FAT filesystem, containing the uImage.
|
|
- Second partition formatted as ext2 or ext3, containing the root filesystem.
|
|
|
|
Create the SDcard partition table
|
|
----------------------------------
|
|
|
|
Determine the device associated to the SD card :
|
|
|
|
$ cat /proc/partitions
|
|
|
|
Let's assume it is /dev/mmcblk0 :
|
|
|
|
$ sudo fdisk /dev/mmcblk0
|
|
|
|
Delete all previous partitions by creating a new disklabel with 'o', then
|
|
create the new partition table, using these options, pressing enter after each
|
|
one:
|
|
|
|
* n p 1 2048 +10M t c
|
|
* n p 2 22528 +256M
|
|
|
|
Using the 'p' option, the SD card's partition must look like this :
|
|
|
|
Device Boot Start End Blocks Id System
|
|
/dev/mmcblk0p1 2048 22527 10240 c W95 FAT32 (LBA)
|
|
/dev/mmcblk0p2 22528 546815 262144 83 Linux
|
|
|
|
Then write the partition table using 'w' and exit.
|
|
|
|
Make partition one a DOS partition :
|
|
|
|
$ sudo mkfs.vfat /dev/mmcblk0p1
|
|
|
|
Install the binaries to the SDcard
|
|
----------------------------------
|
|
|
|
Remember your binaries are located in output/images/, go inside that directory :
|
|
|
|
$ cd output/images
|
|
|
|
Copy the Linux kernel:
|
|
|
|
$ sudo mkdir /mnt/sdcard
|
|
$ sudo mount /dev/mmcblk0p1 /mnt/sdcard
|
|
$ sudo cp uImage /mnt/sdcard
|
|
$ sudo umount /mnt/sdcard
|
|
|
|
Copy the rootfs :
|
|
|
|
$ sudo dd if=rootfs.ext3 of=/dev/mmcblk0p2 bs=1M
|
|
$ sync
|
|
|
|
It's Done!
|
|
|
|
Finish
|
|
======
|
|
|
|
Eject your µSD card, insert it in your Lego EV3, and power it up.
|
|
|
|
To have a serial console, you will need a proper USB to Lego serial port
|
|
adapter plugged into the EV3 sensors port 1.
|
|
See:
|
|
- http://botbench.com/blog/2013/08/15/ev3-creating-console-cable/
|
|
- http://botbench.com/blog/2013/08/05/mindsensors-ev3-usb-console-adapter/
|
|
|
|
The serial port config to use is 115200/8-N-1.
|