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Re: eCos invalidating JTAG on ARM architecture ?


A little update on that, the problem does not occur if i use
cyg_usr_start instead of main as an entry point.

On 7/5/07, Alexandre <thekyz@gmail.com> wrote:
Hi everyone,

I finally manage to run eCos on my eval board (yipee!) thanks to all
of you guys but i have a slight debugging problem (again i know, I'm a
problem maker -.-).

After I upload my eCos code to my board via JTAG (code which is fully
functioning by the way), I can't by any mean reach it again via JTAG.
OpenOCD just says it can't communicate with my board. Seems like eCos
just disable my JTAG. The only way I can access my micro controller
again is by UART, erasing the flash using ISP, and then reflashing it
by JTAG works anew. So it works, but I can't debug the thing.

I lurked through the mailing list to see if anything like that
happened to someone and couldn't find anything so my first guess is I
did something wrong (I'm a pessimistic person).

There are two JTAGs available on my micro controller, one is supposed
to be always enabled when a definite input is pulled to LOW by
hardware means (which I've done, this is the way I manage to upload
the eCos code in the first ways). The second JTAG is enabled by
registry means.

I tried to upload a dummy code without ecos and the first JTAG (the
hardware enabled) works perfectly without any init. The second one
(the software enabled) works also if I input the correct init (which I
did, I mean I managed to make it work ^^).

But with eCos, neither works :(
I tried to put my init code from the dummy software in the eCos init
but I can't make the second JTAG work and the first one isn't working
either.

I was guessing maybe eCos init for ARM (or maybe the olimex lpc2106
port) may have a thing which disable JTAG. Is it possible or did I do
something wrong and JTAG should work with eCos ?

For reference I use an LPC2106 ARM7 micro controller.


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