FDI
NXP LPC3180 Demo
User’s Manual
FDI
Rev 2
Page 9
10/1/2007
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.
On startup, the three LEDs located just above the LPC3180 will blink indicating CPU
activity. Following this the LEDs will count from 1 to 5 in binary as SIBL progresses
through various stages. This is useful in circumstances when the GUI board is not
plugged in and a HyperTerminal connection is not being made from a Host PC.
The functional test mode may be entered by either holding down the F1 key on the
keypad of the GUI board or the space key on the keyboard of the Host PC running
HyperTerminal. For details on the purpose and use of the functional tests, please consult
section 9.0 Functional Test.
The SIBL must be programmed into NAND flash with a special tool that also sets the
first 512 bytes of the NAND flash to an appropriate configuration.
Summary of Contents for LPC3180
Page 32: ...FDI NXP LPC3180 Demo User s Manual FDI Rev 2 Page 32 10 1 2007...
Page 33: ......