Re: [avr-gcc-list] bootloader problem

[Yannick PODGORSKI]

Hi Terry,
I'd got the same problem few weeks ago.
When the BOOTRST is programmed, the problem that is your mega128
resets when it jumps to the app. So, bootloader section starts again.
For me, that was the watchdog that resets the mega128 because I'd got
a tempo without wdt_reset().

In fact, when you make a jump, all configurations are kept. So see what
can reset your mega128 and stop it before your jump or do it at start
of your app.

I think your code is good.

Hope that help.


Yannick Podgorski
www.kuantic.com

----- Original Message ----- 
From: "Lee Terry" <address@hidden>
To: <address@hidden>
Sent: Thursday, January 27, 2005 3:07 AM
Subject: [avr-gcc-list] bootloader problem


> 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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