TMS320C6748 ROM Bootloader code and EMIFA Extended Wait Mode.

The extended wait mode is disabled, and so EW = 0.

Jeff

Jeff, Daniel:

Thank you for your help.

I have another question on the same subject (I know this is going to sound unorthodox, but bear with me):

If:

• I use the NOR flash boot mode of the TMS320C6748, and...
• In the Configuration Word I specify "Direct NOR Boot", and...
• I execcute a few instructions from the external "NOR Flash" and then..
• I execute (again from the "NOR Flash") a jump instruction to the location, within the ROM boot loader code, where the ROM boot loader code has already determined that an AIS NOR Boot is to be performed and this code will proceed to read the AIS image from address 0x60000004 and complete this process as if the "Direct NOR Boot" had never happened.

Then I will accomplish what I need to do.

I realize that in order for this to work:

• The data read from address 0x60000004, would have to have morphed from when the "Direct NOR Boot" mode is executing code from this area to when the ROM Boot loader starts reading the AIS image from the very same area.  This is not a problem.
• I need know the exact address where to jump to within the ROM boot loader code.  Is this a problem?? 

So, finally, here is the question for you:  Will TI be willing to provide an assembly language listing, with hard addresses, for the ROM boot loader code?  And continue to make this information available when it changes? 

Please let me know.

Rafael

Rafael,

I don't possibly see how this would work.  The NOR config word would sit at 0x60000000 and these "few instructions" you mention would need to sit at 0x60000004 and the following locations.  Then if you jumped back into the ROM bootloader and tried to get AIS data from the NOR flash, it would expect to see an AIS magic word at 0x60000004 and valid AIS commands at the following addresses. This doesn't seem possible.

Can you back up and explain why you think you need this convoluted procedure?  Is there some bit of code that you want to run very early in the boot process?

Regards, Daniel

P.S. The ROM boot loader was not designed to be jumped back into in the manner you describe and therefore there are no plans to expose the addresses of symbols associated with the ROM boot loader program and maintain such a list over time and ROM revisions.

Daniel:

Thank you for respondig.  I did not hold much hope for getting the ROM boot loader info.

To answer your question: Yes.  There is a small amount of code I need to run first, before proceeding with the boot loading process.

In my previous posting I wrote:

"I realize that in order for this to work:

• The data read from address 0x60000004, would have to have morphed from when the "Direct NOR Boot" mode is executing code from this area to when the ROM Boot loader starts reading the AIS image from the very same area.  This is not a problem."

This is indeed possible, which gives me an excuse to use the following quote:

"There are more things in heaven and earth, Horatio, than are dreamt of in your philosophy"  Hamlet, Act I, Scene V.

I will give you two clues:  I had the words "NOR Flash" in quotes in my last post, and the reason that I need to execute a small amount of code is to enable the "Extended Wait" mode of the EMIFA.

Rafael

Rafael,

Do you need every word of the NOR flash to be read in extended wait state mode? Because you can use several methods (all in the form of certain AIS commands) to turn on this feature as the first thing you do immediately following the NOR config word and the AIS magic number. The easiest ones would be using the AIS FUNCTION EXECUTE command for executing the EMIF configuration function or using the AIS SET (or BOOT_TABLE) command to place a new value in the EMIF configuration register for CS2. You can craft the AIS file so that one of these operations is the very first AIS command executed. Would that be sufficient for your needs?

Regards, Daniel