Lpc2000

At 04:48 AM 10/29/05 +0000, Eric Engler wrote:
> > What I haven't seen in any of the descriptions of ANY available
>debugger
> > for the ARM microcontrollers is one with a decent watchpoint
>facility.  One
> > that would allow you to set a break when a certain value was written
>to a
> > certain location or range of locations for instance (while running
>at full
> > speed of course).
>
>I can only think of 2 ways to implement flexible conditional breakpoints:
>
>1) set an undconditional breakpoint "behind the scenes". and when it
>breaks, the PC will request data on memory contents and the PC decides
>if it will break for the user, or if it will reset the breakpoint and
>continue execution. This is slow, but easy to implement.
>
>2) the highest performance is done by downloading some extra assembler
>code to the ARM. Set an unconditional breakpoint, and when it breaks
>the ARM assembly code will evaluate the condition, and decide what to
>do. This is almost full speed, but it's harder to implement.

Neither of those will provide a data watchpoint though which is what I was 
referring to above.  Since in order to implement that you would have to 
single step through the code at the instruction level and evaluate at every 
step.  This would be considerably below full speed.  I suspect that this is 
only possible with a proper ICE and I haven't seen one of those for any 
micro that has a BDM or JTAG interface.

Robert


" 'Freedom' has no meaning of itself.  There are always restrictions,   be 
they legal, genetic, or physical.  If you don't believe me, try to chew a 
radio signal. "  -- Kelvin Throop, III
http://www.aeolusdevelopment.com/