Serial Bootloader No source available

[sarvraj_5]

Hello, 

We are trying to implement the simple serial bootloader AN 12086 on TRK- S12ZVL, the derivative file has been changed to S12ZVL 32, The program compiles, however upon running, pressing the PUSH BUTTON and MCU reset,  it gives an error No source available at 0xFFFFFF. 

Can some one provide some comments regarding this. 

No application is build on the bootloader, 

 ROM           = READ_ONLY   0xFF8000 TO 0xFFFDFF; //allocated last 4kB of Flash for Bootloader

[RadekS]

Hi Sarvraj,

How did you make an MCU reset? By RESET button or by the button in CodeWarrior.

That warning “No source available at 0xFFFFFF” sounds like a problem with BDM connection with MCU.

If you reset the MCU externally, the BDM connection is lost and CW debugger will be confused.

Please check also your settings regarding security byte. The last byte from backdoor_array[] @0xFFFE0F should be 0xFE, otherwise, the MCU is secured and cannot be read by the debugger.

The security byte value for AN12086 is defined by SECURE_MCU macro value in Config.h file.

I hope it helps you

Have a great day,
Radek

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[sarvraj_5]

Thanks Radek for the reply, following your advice, i was able to go to the Boot display menu, the problem i face is 

1) The Timer ISR gets longer when i go from application to Boot and then back to application. ( 4 times slower)

2) Upon powering on the board(reset), i want it to jump to application, however it jumps to boot. 

Thanks again.  

[RadekS]

Hi Sarvraj,

I am afraid that I am not sure what you mean by “Timer ISR gets longer”.

The switch between AN12086 bootloader and user application is made through MCU reset.

The simple jump between Boot and App codes may be dangerous due to write-once configuration registers.

The MCU execute Dispatcher() code as first after MCU reset.

The default Dispatcher() code starts Bootloader when:

• PUSH_BUTTON is active,
• Or when EEPROM at BL_REQUEST_ADD address contains BL_REQUEST_VALUE value
• Or when User Application was not successfully loaded before into MCU (Application reset vector at APPLICATION_RESET_VEC_ADD address is empty = 0xFFFFFFFF).

However, you may modify the Dispatcher() code according to your needs.

I hope it helps you

Have a great day,
Radek

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