Lpc2000

David Hawkins wrote:

> 
>  > I'm not sure what's going on here, but I appear to be having a reset
>  > problem with the Keil development board.
>  >
>  > I am using CrossWorks for the ARM and a Olimex Parallel JTAG adapter, or
>  > a USB CrossConnect (both exhibit the same problem).
>  >
>  > On initial powerup, download of code and debug the code runs as expected
>  > (some interrupt code and a counter to indicate that the interrupt is
>  > being run).
>  >
>  > If I recompile (with or without change, it doesn't matter) and reload it
>  > then sometimes the code won't work. Or will partially work (eg. running
>  > in the main loop flashing LEDS ok, but the irq isn't executed -- counter
>  > is at 0).
>  >
>  > I've tried various combinations of stopping and reloading, software
>  > reset of jtag adapter, etc. Pushing the reset button on the board, etc.
>  > The only thing that consistently works is pulling power from the board
>  > before reloading. If I have to do that every time I change the code I'm
>  > going to go nuts.
>  >
>  > Has anyone seen this before? Or has any ideas?
> 
> An idea:
> 
> When debugging with JTAG, often the program runs out of SRAM.
> Unless the loader explicitly clears RAM (eg. the .bss area),
> then there is a chance that you will see differences between
> a cold start (pulling the plug) versus a warm start (any form
> of reset).
> 
> So, if you code looks at some variable that you assume to be
> zero - change it to explicitly set that variable to zero
> (making it part of the data section).
> 

The startup code from Rowley clears ram first I think, and all my 
variables are initialized at powerup anyway. It seems to be related to 
the hardware registers, maybe the VIC setup, that are causing problems.

Brian


-- 
-----------------------------------------------------
Brian C. Lane (W7BCL)                      Programmer
www.shinemicro.com   RF, DSP & Microcontroller Design