Lpc54102 iap ram to flash

[svensavic]

I am trying to make a secondary bootloader and I have issues copying data from RAM to flash.

I prepared the sector (command 50), erased the page I want to write into. No errors up to this point.  Then when I call (command 51) write RAM to Flash, I get return value = 2. “Ram address not a word (or something like that).” Buffer address is at location 0x02000082 (read from debugger). Page I want to write into is 0x00008000 and data buffer is 256 bytes long.

What could be the cause of this error?

i read in user manual that I need to disable ISR. Is that just a case of having all NVIC ISR=0 or there is something else that needs to be disabled?

[converse]

Your ram needs to be 4-byte (word) aligned. So, the address needs to end with a 0,4,8, or C. Your address is only 2-byte aligned.

[svensavic]

I see. Is that the start address requirement or end address? I dont have idea how to force static allocation of buffer at certain location.. I suppose by shuffling variable position in the code? Will that address be guaranteed when optimizer kicks in? Or is there a way to guard part of memory that I need for my buffer?

I am writting the code in C. 

[converse · Accepted solution]

You can never rely on hope for alignment!

instead use the compiler directive when declaring the variable

__attribute__ ((aligned (4)))

Place the directive before your declaration. 

See here for more information 

Using the GNU Compiler Collection (GCC) 

[svensavic]

That is handy to have cheatsheet. Thanks for that.