Hawkboard/BeginnersGuide

 Access Beginners Guide to Programming on Hawkboard http://elinux.org/Hawkboard/Programming_Guide_-Linux(ARM)

Introduction
Hawkboard is an open-hardware project which uses Texas Instrument's (TI) OMAP(open multimedia application platform) Processor(OMAPL-L138). It has both a DSP and an ARM Processor.


 * ARM-This normally runs an OS such as Linux \ Android etc. ARM in OMAPL-138 ,is ARMV5/ARM926
 * DSP- This is a specialized processor for performing Image,Audio and Video encoding/Decoding. These type of processor are  specifically designed to perform these operations faster. DSP in OMAPL-138 ,is C674x Floating Point DSP.

Mix of ARM & DSP (OMAP) gives high performance and low power computing platform,Which are normally used in embedded and mobile Devices.

A Similar kind and a very popular Open-hardware platform is  beagleboard that uses Faster OMAP from TI.

Command usage in this guide
In this guide, commands are preceded by prompts that indicate the environment where the command is to be typed. For example:


 * host$
 * Indicates command to be typed into the shell window of the host Linux workstation.


 * Hawkboard.org>
 * Indicates commands to be typed into the U-Boot shell in a console window connected to the Hawkboard's serial port.


 * target$
 * Indicates commands to be typed into the Linux shell in the terminal window connected to the Hawkboard's serial port or TTY..

Things you will need
1. Hawkboard

2. 5V 1Ampere Power Supply (Atleast 700mA recommended ,As long as volatage is 5V a higher ratings like 1A,2A even more can be used)

3. USB Hub (Hub that provides external power supply is recommended) A USB Hub is highly recommended As you might want to connect multiple peripherals like Keyboard,mouse ,USB Storage devices.

4. Cross Cable DB-9 Female at both ends See wiring diagram below how to make one.

5. SD Card or USB Pendrive (1GB Minimal)

6. Ethernet Cable

7. Ethernet HUB or Switch If you PC/laptop/Router has only one LAN Port which is already in use ,Then might consider purchasing it.

8.System Running Linux either on Real Machine or Vmware/VirtualBOX

Preparing Hawkboard
Before all first thing is to check that the board is properly working or not.

a) Connect a 5V and 1A Power supply (Inner Pin +Ve and Outer GND)

b) Connect VGA monitor cable to Hawkboard VGA Port

c) Power on the Device ,you will see Hawkboard Logo on the monitor as below ,this is due to Bootloader (U-boot) present in the Hawkboard.

d) Further Also check whether you are receiving the Data from Hawkboard UART/Serial port to PC/Laptop Serial port. Serial port will be used to send parameters to bootloader(u-boot).

Connect UART/serial port of Hawkboard on to PC by NULL cable which has DB-9 Female at both ends & It must be crossed i.e and 2 & 3 Interchanged at both ends.

Below is Wiring Diagram



e) Once cable has been connected use following software depending on your system.


 * Hyperterminal or Teraterm -if you are using windows.
 * Cutecom or minicom -if you are using Linux

& Set following parameters to see uboot messages
 * Bits per Second: 115200
 * Data Bits: 8
 * Parity: None
 * Stop Bits: 1
 * Flow Control: None
 * Transmit delay: 0 msec/char, 10 msec/line (Optional)

host$ apt-get install cutecom host$ cutecom &
 * Using Cutecom (Linux)

Set comport
 * 1) If you are directly using PC/Laptop that has comport then it will be probably /dev/ttyS0 -COM1 or /dev/ttyS1 if COM2
 * 2) If you are USB RS232 converter than comport will be something /dev/ttyUSB0

Cutecom ScreenShot below



Start->Run->hypertrm or  Start-All program-Accessories-Communication-Hyper terminal select appropriate Comport
 * Using Hypertermincal (Windows)

As shown below screenshot of Hyperterminal settings

Now power on the Device you should see some text message on Serial Console (Hyperterminal or minicom etc)



Pressing enter will again give a new Hawkboard.org> Prompt.

This shows that serial port is working to send and receive messages to/from hawkboard

{{Note | If you don't see above screen There are two LEDs situated near the serial port (one for RS232 transmit & one for RS232 receive). One of them blinks while the board boots. Showing that is transmitting data to the serial ports. If that Led is blinking then either your cross cable should have a problem or it should be loose connection.

If you are not getting anything on VGA Monitor or COM Port Follow: Recovering U-Boot on Hawkboard

Introduction to uImage ,uBoot & File-system
A Desktop system needs kernel and various application for it to be useful. Similarly, embedded devices also need a Kernel that manages/allocates resources & Schedule task & Set of Applications to perform user task.

The components here are:

This is similar to Vmlinuz (Linux Kernel that grub loads) that exists in Normal Desktop Environment usually in /boot folder.
 * uImage :- uImage is a Linux Kernel (2.6.x) that Bootloader (Uboot) Loads which then finally mounts the (RootFS) Filesytem. The filesystem can be either on SD Card / USB Drive or on Another Network PC through NFS (Network File System) Protocol.

Filesystem is also known as Root Filesystem ,It basically contains all the application (ls,cat,vi etc ),directory structure /dev, /proc, /bin, /etc, /lib, /usr, /tmp & necessary scripts (rc, inittab, fstab etc).
 * RootFS :-Kernel itself is A manager of resource and does nothing useful to user,you need a filesystem for Kernel to manage and you to work upon and provide apps to user.

Preloaded Bootloader in Hawkboard is U-boot.Similar to Like GRUB for Linux and NTLDR for Windows
 * U-boot  :- The third component Known as Bootloader  actually Loads Kernel in RAM.

Download Kernel & Root FS
Download the Sample uImage & Root Filesystem(RootFS) from The Link below

Kernel will loaded through TFTP Server.Though u-boot can load this image from USB/SD Card but the Preloaded (Uboot) that comes with Hawkboard cant access USB/SD Card hence cant access & load uImage.Once the uImage is loaded it can then Access SD/MMC to load Root Filesystem.
 * uImage :- Kernel Image http://hawktool.googlecode.com/files/uImage_v1

(NB:Newer kernel image uImage_v3 contains support for 800x600 resolution and dsplink)
 * RootFS :- Filesystem http://hawktool.googlecode.com/files/RootFS_v1.tar.bz2

Filesystem can be loaded through NFS or SD/USB Drive once uImage is loaded and executed.

The Sample RootFS contains Ubuntu Jaunty Non-Graphical distribution ,which contains  gcc,ssh vi editor and lot more. With gcc you can do native development on Hawkboard itself & No cross compiler needed. For installing new packages you can also use "apt-get install "

Installing and setting TFTPD on PC(Needed for uImage Transfer to Board)
Since TFTP Server is required on Host System to Transfer uImage to Hawkboard ,Install TFTP Server by following steps below:

1. Install tftpd and related packages. host$ sudo apt-get install xinetd tftpd 2. Create /etc/xinetd.d/tftp and put this entry:

service tftp { protocol        = udp port           = 69 socket_type    = dgram wait           = yes user           = nobody server         = /usr/sbin/in.tftpd server_args    = /tftpboot disable        = no  }

3. Make /tftpboot directory

host$ sudo mkdir /tftpboot host$ sudo chmod -R 777 /tftpboot host$ sudo chown -R nobody /tftpboot

4. Start tftpd through xinetd

host$ sudo /etc/init.d/xinetd restart

5.Place uImage_v1 in /tftpboot dir

Preparation for transferring Root Filesystem
RootFilesytem can be loaded to Hawkboard either using SD/MMC or NFS.

If you want to use SD Card or USB Pendrive for loading the RootFS ,you can skip this section and proceed to SD/USB Drive Booting section.Also in case you are facing difficulty setting up NFS Server ,Following Using SD Card or USB Card Methodis recommended.

Using NFS Server Method
In NFS Boot method Root Filesystem remains on host PC & is shared using NFS Server. uImage mounts this NFS Shared folder as its root-file system. Since its shared files can be accessed from Hawkboard else-well as Host Machine,any changes is reflected on both.This method do not require you to Copy RootFS on SD Card/USB Drive. Development is faster since u can directly copy files from Host machine to NFS Folder and it will reflected back on Hawkboard.

Follow these steps to configure NFS Server 1. Install NFS Server host$ sudo apt-get install portmap nfs-kernel-server

2. Share the Folder containing extracted RootFS (e.g /nfsroot contains RootFS)

Edit /etc/exports and add the shares:

/nfsroot (rw,sync,no_subtree_check,no_root_squash)

e.g, /nfsroot 192.168.0.0/255.255.255.0(rw,sync,no_subtree_check,no_root_squash)

Assuming your network is is 192.168.0.0

3.After setting up /etc/exports, export the shares:

host$ sudo exportfs -ra

restart the nfs-server if required host$ sudo /etc/init.d/nfs-kernel-server restart

4.cp RootFS_v1.tar.bz2 to /nfsroot and extract files using host$ sudo tar xvf RootFS_v1.tar.bz2

Using SD Card or USB Card Method
Follow these steps only if you are not using NFS Method or Skip to Next Section.

This requires you to copy Root Filesystem to SD Card or USB Pendrive, Drive should have a ext2/ext3 partition and file should be copied on that system. To create ext2/ext3 partition you can use gparted.

1.Install Gparted using apt-get install gparted 2.Now create ext2 partition using gparted /dev/sdb& Note:Here /dev/sdb is USB PenDrive create aroud 2GB or more Ext2 partition



3.Copy RootFS_v1.tar.bz2 to this partition Extract using tar xvf RootFS_v1.tar.bz2 rm -f RootFS_v1.tar.bz2 sync

and remove the SD Card or USB Drive

Booting Linux
Once TFTP Server has been setup and uImage has been placed in /tftpboot folder & Also RootFS has been put in either NFS Folder(/nfsroot) or on SD/USB Card,Next Step is to load the kernel and RootFS.

1.Open Cutecom or HyperTerminal from HOST Machine

2. Enter following command to Load uimage through tftp ( as usual) hawkboard.org> setenv serverip  hawkboard.org> setenv ipaddr  hawkboard.org> tftp c0700000 uImage_v1

at location c0700000 Below shows a Screenshot about how to enter these commands in cutecom
 * 1) PC_IP ->is IP address of your Host Linux machine.
 * 2) BOARD IP ->is IP address if your board you want to setup(you can any address but make sure its on same network)
 * 3) tftp c0700000 uImage_v1 ->Tells Bootloader to Load uImage from PC_IP to Hawkboard's RAM



2.Set Bootargs Bootargs is the parameter/Variable that is send to uImage telling the Location of RootFS. Once the uImage is executed ,it then read bootargs and mount the RootFS from the location described in Bootargs.

Set one of the Following Bootargs depending where your RootFS is located.

a)If USB Drive hawkboard.org> setenv bootargs console=ttyS2,115200n8 noinitrd root=/dev/sda1 rootwait rw init=/sbin/init

Here
 * 1) root=/dev/sda1 Tells that RootFS is locaed on USB Drive on first ext2 partition
 * 2) console=ttyS2,115200n8 tells where to put booting Message,Its basically UART3 of Hawkboard.
 * 3) init=/sbin/init tells which program to run first after mounting rootFS (Leave this as it is)

b)if SD Card 

hawkboard.org> setenv bootargs console=ttyS2,115200n8 console=tty1 noinitrd root=/dev/mmcblk0p1 rootwait rw

or

hawkboard.org> setenv bootargs console=ttyS2,115200n8 console=tty1 noinitrd root=/dev/mmcblk0p1 rootdelay = 2 rootfstype = ext2 rw

Here p1 in mmcblk0p1 says that Rootfs is present in first partition of SD Card.

c) If NFS Boot

c.1)If Board uses Static IP

hawkboard.org> setenv bootargs 'console=ttyS2,115200n8 noinitrd rw ip=::: ::eth0: root=/dev/nfs nfsroot=:/nfsroot'

e.g  hawkboard.org> setenv bootargs 'console=ttyS2,115200n8 noinitrd rw ip=192.168.0.125:192.168.0.1:192.168.0.1:255.255.255.0::eth0: root=/dev/nfs nfsroot=:/nfsroot'

where 192.168.0.125 is board IP & 192.168.0.1 is gateway IP& Router IP.

c.2)if Board uses DHCP hawkboard.org> setenv bootargs "mem=128M console=ttyS2,115200n8 root=/dev/nfs nfsroot=:/nfsroot ip=dhcp"


 * 1) nfsroot= location of rootfs
 * 2) root=/dev/nfs tells that root filesystem is located on different PC on a NFS rather on SD/USB Card.

3.Run the Kernel & Mouting of Filesystem hawkboard.org> bootm c0700000 Tells Uboot to run image located at location c0700000 ,in this case its uImage i.e Kernel



Explaining Booting Process
After entering the bootm command the kernel starts executing from RAM. The kernel reads the bootargs argument that was passed as an environment variable earlier. Bootargs describe the location of the root filesystem. Reading this information uImage mounts the RootFS and runs /sbin/init (which typically shows you a login prompt).

Sample rootFS present as download above is configured for following user and password user:hawk password:password