LPC2136 JTAG issue

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Hi guys,
A strange problem on a custom board built using a Philips LPC2136 ARM7TDMI
chip, may be someone will have an idea... :

- Software developped and tested on a Keil MCP2130 eval board (with a
LPC2138), programmed and debugged with a Ulink JTAG probe, no problem
- Recompiled for the target chip (LPC2136), tested on the eval board (as
only the flash memory is more limited), no problem
- JTAG probe connected to the target board, flash program & verify cycle
executes OK, however the firmware is apparently not working at all
- Debug mode with the JTAG on the target board (step by step starting from
reset) : very strange, the instructions displayed are the one from our
firmware, but their behaviour is not consistent with the instruction (ex a
jump doesn't change PC, etc). Seems like the debugger memory and the target
memory are not in synch...
- Tried with a slower speed on the JTAG, same behaviour

I'm 99% sure there is something wrong on the JTAG itself, but I've checked
10 times and it seems well wired. Moreover I don't understand how a program&
verify cycle could be ok if the jtag was wrong... Or something linked to the
LPC rom boot code ?

Any idea will be appreciated !

Friendly,
Robert



Re: LPC2136 JTAG issue
Quoted text here. Click to load it

PROBLEM SOLVED ! Just in case others could have the same issue : P0.14 pin
should be HIGH at reset, if not the LPC launches the on-chip ISP code and
doesn't launch the application, and then the debugger is lost...

Yours,
Robert



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