RE: [U-Boot-Users] Re: [Question About NAND BOOT In SMDK2410
There are a few processors which actually can "boot" from NAND. The OMAP161x is one such processor. It has hardware NAND support for ECC and fetching this along with some microcode in an internal mask ROM (on chip) can load up and execute code contained in Nand for boot.
http://siliconvalley.internet.com/news/print.php/2224021
There is also a couple "integrated" chips which also allow booting from a "mainly" a nand device, like disk on chip and SuperNAND.
http://www.m-sys.com/Content/Products/mobileDocPlusDiagram.asp
As for what the SMDK2410 board is capable of, I have no idea.
Regards,
Richard W.
-----Original Message----- From: u-boot-users-admin@lists.sourceforge.net [mailto:u-boot-users-admin@lists.sourceforge.net] On Behalf Of Wolfgang Denk Sent: Tuesday, October 28, 2003 8:11 PM To: Rod Boyce Cc: choigi@samsung.com; u-boot-users@lists.sourceforge.net Subject: Re: [U-Boot-Users] Re: [Question About NAND BOOT In SMDK2410
In message 8D7C5F56B409554D9D46AC22195807F3061DD3@exchwenz01.dmcwave.co.nz you wrote:
What do you have in mind? Boot U-Boot from a Smart Media Card? [Can't be done.]
[Dear Rod, please stick with standard quotin rules - read the Netiquette if necessary.]
Wolfgang it is code and with code anything can be done I have written code
Arghhh... I have yet to see any processor that can "boot" (i. e. start fetching instructions out or reset) from an NAND flash device. So far, all of them need some software to do this, which must be loaded from a _real_ boot device.
to read and write to a SmartMedia card from an 8051 8-bit micro. If I had
a
But I guess the first instruction the 8051 executed was NOT loaded from the SmartMedia card? I guess there was some ROM which you used as boot device, right?
need to read a kernel out of SmartMedia then I could do that just as
eaisly.
Please read again what I posted. What does "boot" mean? Is it bootstrapping a processor out of the reset condition into some sort of software (typeically a monitor program like U-Boot), or is it using a bootloader to bootstrap an operating system?
At 50MHz processor I could even do an effective ECC and still read it out.
Can't be done. It won't start fetching instructions from SmartMedia when you relese the reset pin.
I have not done this but I can not think of a reason why it cannot be
done.
Think again. Read again. Read before posting, please.
Wolfgang Denk
In message 71555548814716479478431542AA5F8A058D14@dlee2k98.ent.ti.com you wrote:
There are a few processors which actually can "boot" from NAND. The OMAP161x is one such processor. It has hardware NAND support for ECC and fetching this along with some microcode in an internal mask ROM (on chip) can load up and execute code contained in Nand for boot.
So you are booting from an internal ROM in fact (which is similar to the NAND Flash Boot loader contained in the s3c2410x processors).
I know this is nitpicking, but I feel it is essential to use precise terms. Ortherwise one asks a question (I want to "boot" from device XXX) and the answer uses different deinitions of the teerms which renders it useless.
This is especially true when using such an all-embracing term like "boot" or "bootstrap loading" - where does it start (when the processor fetches the first instruction?) and where does it end (when U-Boot prints it's interactive prompt? when a boot loader loads an operating system and passes control to it? when the OS starts the first application code? when the OS has completed starting all system services and enters multiuser mode? or what?) ??
Best regards,
Wolfgang Denk
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Wolfgang Denk -
Woodruff, Richard