Lpc2000

Hi Brian,

The LPC2xxx series can't be brought out of reset under JTAG debug 
control. So you are not getting a hardware reset on each debug run. The 
worse case is a flash resident program that disables JTAG (explicitly or 
going into low power mode). Someone sent one of these to us asking why 
the debugger didn't work - we had to use the serial boot loader to make 
the board JTAG debuggable. The LPC2xxx isn't unique in this respect - 
the same problem affects most ARM chips with on-board flash. It came as 
a pleasent surprise when we discovered that the STR730 can be brought 
out of reset under debug control - a better debug selling point than the 
ETM in my opinion.

Regards
Michael

>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?
>
>Thanks,
>
>Brian
>
>  
>