AVR xmega: Software jump to zero

I've written an encrypted bootloader for the xmega which works now other than for one problem. Once the code is in, I (obviously) need to jump back to zero to execute the new code I've loaded.

I've tried all sorts of things including an assembly routine that simply contains:

jmp 0

after having setup PMIC, RAMPZ and EIND in C code.

I've seen on AVR freaks someone saying these are the steps that need to be taken and the Atmel bootlaoder apps note says a similar thing. However, once I get to the jpm 0, however I try it - in assembler or in C how the AVR apps note suggests, it doesn't work at all. If I set a breakpoint just before jmp 0, it gets there fine, but then stepping into it or over it just sets the program back running and if you break, you're back into the bootloader section.

The disassembly of the jmp 0 line is this:

940c 0000 JMP 0x00000; 0x00000

Anyone know how to solve this please?

Many thanks,

Rob

Jorge

July 14, 2010 16:24

Rob, did you find a solution to your problem ? now I'm working with a xmega256A3 and I have the same symptom that you describe, I loaded de bootloader y seems to be ok, and the the application to 0 vector, but the bootloader never jump to it.

Robert Wood

July 14, 2010 16:33

Afraid not. Client ran out of money, so I haven't touched this for a few months - been on STM32 stuff. When he restarts the project I will need to suss it though. Might have to open a query directly with Rowley.

Michael Johnson

July 15, 2010 10:19

If you can raise it as a ticket and attach the code I'll have a look at it.

Regards

Michael

July 15, 2010 17:52

Thanks Michael, but it's working now, Rob...I used xboot (http://code.google.com/p/avr-xboot/), you can try too, read the manual, if your application use UART beaware of UART_CLK2X bit (you must set it in your application) and use the Makefile (configure for your hw) to compile.

Bye.

AVR xmega: Software jump to zero

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