missed something in the requirements of uCLinux start up.
1. Initialize and provide access to RAM/ROM and peripherals
A. change PLL
B. change chip select registers for RAM/ROM
C. setup AIC
D. setup WDT as necessary
E. ensure other peripherals are in a quiescent state
2. jump to 'stext'
That's good for a first stage bootloader. You might use it in a
rolled out system where you only update to tested firmware, or when
you have pins on the board to easily reflash it.
Often it's useful to have a second stage with options to trap on a
diagnostic serial port, present a prompt, boot an alternative kernel,
read a file from the network and write it to flash, etc. Sometimes
the second stage can be a small Linux kernel :-)
Jamie,
Yes, a more advanced bootloader like U-Boot and others provide these
enhancements. You are correct in that remote or local reflash of target
code can be a requirement. As well as multi-backup boot images in
case a new download failed. I forgot to add i did add a simple memtest
to SRAM. Can quickly grow into it's own monster with unique
requirements. :)
thnx for the enhanced requirement list.
bob
_______________________________________________
uClinux-dev mailing list
uClinux-dev@uclinux.org
http://mailman.uclinux.org/mailman/listinfo/uclinux-dev
This message was resent by uclinux-dev@uclinux.org
To unsubscribe see:
http://mailman.uclinux.org/mailman/options/uclinux-dev
