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[avr-gcc-list] bootloader problem


From: Lee Terry
Subject: [avr-gcc-list] bootloader problem
Date: Thu, 27 Jan 2005 11:07:30 +0900 (JST)

Hi, all.
 
I wrote a bootloader for mega128, and here are the problems.
 
1. BOOTRST programmed 
   I upload an application, then jump to 0x0, bootloader section starts again.
   Below is the code I use when jumping to the app.
 
    boot_spm_busy_wait();
    __boot_rww_enable();
    MCUCR = (1<<IVCE); 
    MCUCR = (0<<IVSEL);
    asm volatile("cli"::);
    asm volatile("jmp 0x0000" ::);
 
 
2. BOOTRST unprogrammed
   After uploading an application, I jump to the app. section using the same 
code I wrote above, the application starts normally. But when I want to jump to 
the bootload section from the app. section, my bootloader program keeps 
restarting. And it seems running slowly.
I changed the clock setting to/from external/internal clock, but it is same.
 
Below is the code that I use to jump from app. to bootloader.
MCUCR = BIT(IVCE);
 MCUCR = BIT(IVSEL);
 __disable_interrupt();
 asm("jmp 0x1E000"); // jump to bootloader-reset-vec
 
 
 
Please tell me what I do wrong....
 
Terry.

                
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