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Altera_Forum
Honored Contributor I
721 Views

Application jump to Bootloader

Hi, 

 

I need some help with triggering an application restart from bootloader.  

 

In my system I have an on-chip RAM (where bootloader resides) and an SRAM where application will be running. The reset vector is located in the onchip RAM. 

If I jump to the reset vector location, the Nios reboots but starts from the application and does not execute the bootloader. 

 

How can I force the execution of the bootloader? 

 

Thanks!
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3 Replies
Altera_Forum
Honored Contributor I
39 Views

Hi, 

 

For this use case, the boot copier used should be CFI based boot copier. 

The application should located just after the CFI based boot copier. 

Wonder is this the boot copier you used or your custom boot copier? 

 

Chin Liang
Altera_Forum
Honored Contributor I
39 Views

Hi, 

 

I had this issue abandoned for a while, not it's buzzing me again. 

 

What is the explanation why the custom bootloader would not execute (reload the application from flash) after a reset although reset vector is located in the same onchipram where the custom bootloader resides?  

 

Thanks
Altera_Forum
Honored Contributor I
39 Views

Altera named our boot-stages as BootROM, Preloader, U-boot or RTOS or Baremetal on 3th stage. 

What you mean by "custom bootloader" ? And why mentioned Nios ? 

Usually 64K of onchip RAM is visible from 0 adress also, although he located on FFFF0000. 

However, some time I see BootROM on 0th disassembly and steped to it in DS-5 -- remapping may be used. If fill Custom Preloader with "while (1) ;" to flash and repower board, may connect to this endless cycle and continue running through changing PC... 

If application calls pure function pointer, then will be reboot of system. If to 0 mapped BootROM, will be full reboot.
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