31
1072_0_Product_Manual - February 24, 2011 2:52 PM
Nand Layout
The board contains 64MB on Nand. This nand is split into 7 partitions as follows:
0: u-boot
size: 256K
Read Only
1: u-boot_env
size: 128K
Read Only
2: recovery_kernel
size: 2M
Read Only
3: kernel
size: 3M
Writable
4: flashfs
size: ~3.625M
Read Only
5: recovery_fs
size: ~ 43M
Read Only
6: rootfs
size: ~ 460M
Writable
The final size of flashfs/recovery_fs/rootfs depends on the image size at production, and on the number/location of
bad blocks in the NAND.
U-Boot and recovery kernel and filesystem cannot be written from Linux - this is a safety measure.
Boot Process
This describes the boot process from power on.
1. Processor loads first 4 bytes from NAND into Steppingstone and runs it.
2. Steppingstone sets up RAM, copies u-boot from NAND into RAM and runs U-Boot.
3. U-Boot initializes the processor, sets GPIO state, etc., copies the linux kernel into RAM, sets up the kernel
command line arguments, checks that the kernel image is valid, and boots it.
4. Linux boots, bringing up USB, Networking, NAND, etc. and then mounts the rootfs NAND partition on /.
5. init gets run as the parents of all processes, as uses the /etc/inittab script to bring up the system. This includes
mounting other filesystems, settings the hostname, and running the scripts in /etc/init.d, among other things.
6. inittab then turns the green LED on.
7. inittab then sets up a getty on the first serial port, ready for interfacing using the debug board.
Drivers for USB to Serial adapters
The SBC kernel contains driver support for the following USB to Serial Adapters.
Please consult the kernel documentation for details into the driver support for the USB to Serial adapters.
Company
Product
ConnectTech
WhiteHEAT
Keyspan
USA-18X, USA-28, USA-28X, USA-28XA, USA-28XB, USA-19, USA-19W, USA-19QW,
USA-19QI, USA-49W, USA-49WLC
FTDI
Single Port Serial Adapter
Cypress
M8 CY4601 Family
Digi International
AccelePort USB Serial
Belkin
USB Serial Adapter F5U103
MCT
USB Single Port Serial Adapter U232
Inside Out Networks
Edgeport Serial Adapter
Prolific
PL2303