CC2541 Store Constants in Code Banks

Elias Zimmermann

Hello,

I have to store ~ 40kB const data (some fonts...). The XDATA_ROM_C (0x8000 - 0xffff) is to small to store all the data so I try to put the data into the code area (using code banks).


#pragma constseg = __xdata_rom BANKED_CODE
const GuiConst_INT8U Ch000015[16] =
{
  2,2,2,2,2,  6,6,6,6,6,
  2,5,
  11,2,
  0x1F,
  0x03
};

I see the correct result in the memorymap (Ch000015 is linked to banked code instead of xdata_rom_c), to address 0x31c9f.

<BANKED_CODE> 6 (was BANKED_CODE)
Relative segment, address: CODE 00031C9F - 00031CAE (0x10 bytes), align: 0
Segment part 21.            Intra module refs:   GuiFont_ChPtrList
           ENTRY                   ADDRESS         REF BY
           =====                   =======         ======
           Ch000015                00031C9F

But when debugging and catching the pointer (void*) of Ch000015, the read out address is not 0x31C9F but 0x9C9F.
I also tried to read the address by using a generic pointer (void __generic *).

How to read out the constants from different code banks correctly?

//* EDIT: Oh, does this known issue concern me? Using IAR EW 8051 IDE 8.20.2

http://supp.iar.com/FilesPublic/UPDINFO/005161/ew/doc/infocenter/icc8051.htm

EW21366
In case the banked code model and the option --place_constants=code is used constants must be placed in the root bank and NOT in a code bank. This is unfortunately still true regardless of whether the device you are working with supports the command line option --has_cobank or not.

greetings,

Elias

over 11 years ago

0 Elias Zimmermann over 11 years ago

Prodigy 250 points

So, is it possible to place constants in code memory (main bank or banked code) without changing code model to "Banked Extended 2" ?

Tried some variants with placing constant arrays by using "#pragma constseg = BANKED_CODE". And tried to reference these constants by using generic pointers. But unfortunatly without success so far.

Are there any possibilities to store constants outside the xdata_rom range, and without changing the whole code / memory model?

Thank you for responses

0 Greenja over 11 years ago in reply to Elias Zimmermann

Guru 22270 points

Hello Elias,

I don't see you having a problem with the first method you used. The data is stored in flash along with your program. There is probably an offset associated with the memory location, I can't remember how exactly it is calculated right now. You should be able to search for it.

There may be a way to search for the memory location using the pointer name in IAR, not sure about that either, but you can read through the IAR IDE guide and see.

Thanks,

Bluetooth®︎

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CC2541 Store Constants in Code Banks