[U-Boot-Users] help in understand the address of standaloneapplications, ARM MCU

[Ulf Samuelsson]

> In message <200805111736.50691.casainho at gmail.com> you wrote:
>> 
>> I am using an Olimex dev. board with a ARM9, AT91SAM9260 MCU. On my makefile I 
> 
> Is this board supported in the public U-Boot git tree?
> 
>> am linking with address 0xc100000, "LDFLAGS=-Bstatic -Ttext 0xc100000" -- is 
> 
> What makes you think we would know the memory map of your board better
> than you?
> 
>> this address correct? How can I have sure of that? -- I got this value from 
>> makefile of "hello world" example.

By looking at the datasheet of the part in questions!

The AT91SAM9260 has fixed decoding of chip selects.
If you want to put your code in SDRAM, you need to put
is somewhere from [0x20000000 .. 0x20000000 + SDRAM_SIZE ]
U-Boot is typically located at  [0x20000000 + SDRAM_SIZE - 0x100000]

> 
> As the first step you have to  understand  the  memory  map  of  your
> system. We cannot know this.
> 
>> When I do "tftp 0xc100000 flash_led.bin" the system hangs.. while If I try to 
> 
> Then the address is obviously wrong - seems there is no RAM there.
> 
>> do for example "tftp 0x1000 flash_led.bin" the code loads ok but after "go 
> 
> Are you sur the code is really stored to this  address?  I  seriously
> doubt  that.  0x1000  is  probably an address in flash memory on your
> system, and you do not program the flash (normally)  when  running  a
> "tftp" command.
> 

0x1000 looks like internal SRAM. This is VERY limited in size.

>> 0x1000", the code does not work... It evens return while shouldn't because of 
>> an infinite loop on the code.
> 
> You are probably executing random code that happens to be at that
> location in flash.
> 
>> In the manual of the dev. board I have a memory map that says the 64MB RAM 
>> starts at 0x20000000 and ends on 0x23FFFFFF - If I do "tftp 0x20000000 
> 
> Ah, see! So what makes you think 0xc100000 could work?
> 
>> flash_LED.bin" system also hangs...
> 
> Probably because you are overwriting the exception vectors?
> 
>> I must say that with my dev. board comes an "hello world" example which is an 
>> empty function :-( -- but even I don't know to what address I should load it.
> 
> Ask the company who provided that port of U-Boot and the example
> program?
> 


Best Regards
Ulf Samuelsson