Linuxstamp II 9260
The Linuxstamp is designed to be a general purpose processor module. It is designed to work as a stand alone module (SD card, Ethernet and USB/Serial converter are all on the module). This allows all initial development to be done without a motherboard, but for integration into a specific project a motherboard with specific features could be designed. Check out the start of the first mother board for the Linuxstamp, Mboard 1.
- Atmel AT91SAM9260 processor (Arm9 processor with MMU, 200Mhz operation)
- 32MB SDRAM
- 8MB SPI Dataflash
- 1x 10/100 Ethernet
- 1x USB host port (allows wifi adapters, flash drives and other USB devices to be used)
- 1x micro-SD card slot
- Serial debug port 5-pin header
- JTAG port
All files for this project are licensed under the GNU GPL V2
Hardware design files
Warning!!! Use this design at your own risk.
The power supply for the board is based on the Linear LTC3407-3. This is a very compact high frequency switching power supply. It has both a 3.3v and a 1.8v output. It does have a very tight input range 3.3v-5.5v. The Micrel PHY also needs 2.5v, but this is provided by an internal regulator. Currently a regulated 5v must be used to power the board.
Minicom & the debug port
The mini-USB device port on the Linuxstamp does not connect directly to the AT91RM9200 it connects to the FT232R chip. The FT232R is a USB/serial converter. The FT232R chip has drivers for both Windows and Linux, but the Linux drivers are included in later kernels. Drivers for Mac OS X are available here.
When you plug the Linuxstamp into your host (Linux) machine a device should appear /dev/ttyUSB0 (the suffix number will increment as you add more devices). /dev/ttyUSB0 will behave as any other serial port now. Minicom is the standard program to access the serial port in Linux. The first time you run minicom you will have to be root in order to do the setup, after that you can change the permissions on /dev/ttyUSB0 so any user can run minicom. To enter configuration mode in minicom type CTRL-A o, now scroll down to Serial port setup. Use the letters to navigate. You will want the device to be /dev/ttyUSB0 and Bps/Par/Bits to read 115200 8N1. Both hardware and software flow control should be OFF. Connection to the board is important for loading Atmel's tiny program and u-boot, but once the board is working it might not be as important.
Another alternative is to use HyperTerm on Windows, which works fine with the Hardware boot loader. If you are updating the Darren Bootloader, note that the loader only has a short delay after you initiate the "receive" (on the loader) after which it send out the "ready to receive" signal. As a result, you'll need to be rather quick to initiate the Xmodem "send" (on HyperTerm). If you are seeing time outs on HyperTerm when you try and send the loader.bin file, you are probably hitting this problem ... you need to have initiated the send before you see the "C" on the screen from the bootloader.
nfs & tftp
Nfs (network file system) and tftp (trivial file transfer protocol) are two servers you will want running on your host machine. Nfs is useful for hosting the root file system of the Linuxstamp. Tftp is useful for u-boot to retrieve the kernel from. There are many other websites on nfs and tftp, but I will try and go over a simple setup. I would suggest being behind a firewall before trying either of these setups as neither is secure. I wrote this using a Fedora 7 system. First make sure you have nfs installed.
$ yum install nfs-utils nfs-utils-lib portmap system-config-nfs
On Ubuntu (or other debian-style systems) you could use:
$ sudo apt-get install portmap nfs-kernel-server nfs-common
Now to make sure the service is enabled run (this won't work on Ubuntu):
$ serviceconf and make sure nfs and nfs lock are checked
Now edit /etc/exports you should add a line like this /path_to_nfs_root/ *(rw,no_root_squash,insecure). Now restart nfs.
$ sudo /etc/init.d/nfs restart
You can test that it is set up correctly by typing the following on the local system (i.e. right on the NFS server)
$ showmount -e localhost
You can test this from a remote system with
$ mount -t nfs server_name:/path_to_nfs_root /path_to_test_mount
Now on to tftp. Make sure it is installed.
$ yum install tftp-server
This will create a file /etc/xinetd.d/tftp. In this file you will want to change disable from yes to no. Now make a test file.
$ cd /tftpboot $ echo hello > file
Now we can test it
$ tftp -v server_name -c get tmp
Now with u-boot we can load image files
> tftpboot 20800000 uImage
And boot them
> bootm 20800000
- : Up to date kernel patch for the AT91 parts
- Cadsoft.de: Free (as in beer) tools for schematic and PCB design
- openhardware.wordpress.com: Here is my openhardware blog
- App notes: for Atmel arm processors
- Mborad 1 for the Linuxstamp
- ECB AT91 This is another open source project similar to the Linuxstamp. They have some very good documentation.
- Budgetdedicated Graciously hosts our ftp site
Please join the google group for the Linuxstamp discussion http://groups.google.com/group/linuxstamp
For further questions or comments please contact Paul (pthomas8589 _at_ gmail _dot_ com)