Lpc2000

You can also enter the JTAG debugger while in the bootloader code. This 
way you do not need to erase the chip via the serial lines (which are 
inaccessable on my board). I always put a jumper on the board to pull 
P0.14 low when I screw something up badly. Also JTAG programming does 
not work well when you use the idle mode, so it helps to first force it 
in bootloader mode and then program the chip with the JTAG programmer.


Lowry, Jeff wrote:

> I've had this happen.  What I had to do was reset the chip with P0.14 
> low to force it into ISP mode.  I then manually did the ISP commands 
> via RX0/TX0 to erase the chip.  Once erased the JTAG will take control ok.
>
>       -----Original Message-----
>       From: lpc2000@yahoogroups.com [mailto:lpc2000@yahoogroups.com] 
> On Behalf Of Tom Walsh
>       Sent: Monday, October 24, 2005 1:09 PM
>       To: lpc2000@yahoogroups.com
>       Subject: Re: [lpc2000] destroyed LPC2138 via software
>      
>      
>       Tom Walsh wrote:
>      
>       >This is not good.  I ran some code on the LPC2138 board of mine 
> to track
>       >down a Data Abort that was being thrown.  Merely commenting out 
> sections
>       >of code.  Now, after running that code on two boards, dumping 
> memory via
>       >BDI2000 + JTAG I get a "Data Abort" when it attempts to dump 
> anything
>       >above 0x0000:0040!
>       >
>       >Anyone else run into this?  That is it possible to destroy an 
> LPC2000
>       >chip via software?
>       >
>       > 
>       >
>       Nothing like answering my own question.
>      
>       The problem appears to be the time interval between when the 
> JTAG unit
>       asserts a hardware RESET and until it is able to seize control 
> of the
>       CPU via the tap interface (JTAG).  During that interval, the 
> processor
>       runs like hell and hits the abort'ing code.  Finally the JTAG is
>       operational, but now the CPU is abort'ed.
>      
>       For some really strange reason, the JTAG has no control over an 
> aborted
>       processor?!
>      
>       The chip is not destroyed as I feared, it is merely totally 
> fsck'ed and
>       won't work with the tap controller.
>      
>      
>       TomW
>      
>       --
>       Tom Walsh - WN3L - Embedded Systems Consultant
>       http://openhardware.net, http://cyberiansoftware.com
>       "Windows? No thanks, I have work to do..."
>       ----------------------------------------------------
>      
>      
>      
>      
>      
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