FDI LP3180, User Manual, Page: 12 / 40

FDI
NXP LPC3180 Demo
User’s Manual
FDI
Rev 2 Page 12 9/7/2007
5.0 Boot Process
This section provides a detailed description of the boot process for the LPC3180 board.
First, a general list of steps is given as an overview to the boot process. A more detailed
explanation is then provided for the main applications responsible for loading Linux on
the LPC3180.
The boot process of the LPC3180 project is broken up into the following general steps:
1. On power-up, the LPC3180 begins booting by reading block 0 from the NAND
flash.
2.
The secondary boot loader called SIBL is loaded from NAND flash, stored in the
LPC3180’s internal RAM, and executed.
3. SIBL performs initialization commands on the LPC3180 and loads the u-boot,
Linux Kernel, and root filesystem images from NAND flash into SDRAM at
predefined locations.
4. U-Boot is then executed which performs other checks and initialization steps and
finally executes the Linux Kernel image already in memory.
5. Linux boots using standard SysV Init and automatically modprobes all required
kernel modules.
6. The user may then log into the LPC3180 board as superuser “root” with no
password.
5.1 SIBL
The SIBL is the secondary boot loader that is executed before U-Boot. SIBL is
responsible for most of the required initialization and also provides a mechanism to run
functional tests on the LPC3180 board. A list of SIBL’s main responsibilities includes:
1. Lock in the PLL to allow the LPC3180 to run at 208 MHz
2.
Initialize, configure, and perform a quick read/write test on the SDRAM
3. Setup NAND controller and load the images out of Flash to SDRAM
4. Perform a CRC check on loaded images to verify their integrity
5. Walk through blocks in SDRAM until an executable image (U-Boot) is located
and run.