Questions about the FMI registers (bootloader)

[splouzennec]

Posted on December 10, 2009 at 17:43

Questions about the FMI registers (bootloader)

[splouzennec]

Posted on May 17, 2011 at 09:59

Hello,

I work with the STR9FA12W47, with bank0 = 2048kB and bank1 = 128kB. And I have some questions about the using of the FMI registers.

I build a bootloader in the bank1, witch jumps into the bank0, where there is my user application. So my boot bank is the bank1 (128kB). When I jump, I have to remapping my configuration of boot bank.

Here the code of the jump function

void __ramfunc ROM_Jump (void)

{

pFunction JumpTo;

// before change mapping, disable all VIC

VIC0->INTECR |= 0xFFFF;

VIC1->INTECR |= 0xFFFF;

// Change mapping:

FMI->BBADR = 0x200000 >> 2;

FMI->NBBADR = 0x0;

JumpTo = (pFunction)0x0;

JumpTo();

}

This code is working very well ! :)

But When I try to redefine the Boot and Non Boot Bank size my application crash..

Here the code of the function jump that causes a crash of the user application.

void __ramfunc ROM_Jump (void)

{

pFunction JumpTo;

// before change mapping, disable all VIC

VIC0->INTECR |= 0xFFFF;

VIC1->INTECR |= 0xFFFF;

// Change mapping:

FMI->BBSR = 0x6;

FMI->NBBSR = 0x5; //0x4

FMI->BBADR = 0x200000 >> 2;

FMI->NBBADR = 0x0;

JumpTo = (pFunction)0x0;

JumpTo();

}

So the only difference between the two codes is the redefinition of the FMI->BBSR and FMI->NBBSR.

It is the reason why I post this message. I would like to know how STR9 uses this register ? What are their impacts on the STR9 ?

If somebody have the answers of this questions, please let's me to kown it :D

[tomas23]

Posted on May 17, 2011 at 09:59

It *may work*, but I recommend not to remap. Boot always into Bank 1 (set permanently by JTAG) and implement something like ''IVT forward'' in RAM.

This approach works fluently, the cost is first 64 bytes of RAM are wasted by IVT, and a little different start-up routine.