LPC2136 JTAG issue

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

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Robert Lacoste
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"Robert Lacoste" a écrit dans le message de news: 43786cdc$0$18329$ snipped-for-privacy@news.wanadoo.fr...

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

Reply to
Robert Lacoste

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