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LPC2194 JTAG programming problems...

Started by gregdeuerling November 15, 2004

I've two Philips LPC designs. One uses a LPC2294 and the other a
LPC2194. I've been working on the LPC2294 design for some time and
have not had any problems at all. My LPC2194 design is a different
story. I'm using the Keil DKARM (V1.4) and ULINK to program the
LPC's via JTAG. My LPC2194's program the 1st time but from then on
out I get an error saying:

"JTAG Communication Failure", "Error: Flash download failed - Target
DLL has been canceled".

I've stuck on 3 other LPC2194's and each has failed in the same way.

I have the proper crystal freq. selected in the target settings
(12Mhz). I have "ULINK ARM Debugger" selected in the "Use target
driver for flash programming" field, and I have "LPC2000 IAP 256KB
Flash" selected for the programming algorithm.

Like I said, I use the same setting above for a LPC2294 and it works
fine every time. The parts that fail to program a second time run
their initially flashed program just fine, I just can't get at the
JTAG port.

I've searched the threads here and the LPC2194 errata and see there
are some programming problems with devices with early date codes.
But that problems seems to be a lockup during programming, not what
I'm seeing. I've contacted Keils support vie email, I thought I'd
try here also to see if anyone else has seen this...

Any ideals, I'm stumped?



An Engineer's Guide to the LPC2100 Series


--- In , "gregdeuerling" <egads@f...> wrote:
>
> I've two Philips LPC designs. One uses a LPC2294 and the other a
> LPC2194. I've been working on the LPC2294 design for some time
and
> have not had any problems at all. My LPC2194 design is a
different
> story. I'm using the Keil DKARM (V1.4) and ULINK to program the
> LPC's via JTAG. My LPC2194's program the 1st time but from then
on
> out I get an error saying:
>
> "JTAG Communication Failure", "Error: Flash download failed -
Target
> DLL has been canceled".
>
> I've stuck on 3 other LPC2194's and each has failed in the same
way.
>
> I have the proper crystal freq. selected in the target settings
> (12Mhz). I have "ULINK ARM Debugger" selected in the "Use target
> driver for flash programming" field, and I have "LPC2000 IAP 256KB
> Flash" selected for the programming algorithm.
>
> Like I said, I use the same setting above for a LPC2294 and it
works
> fine every time. The parts that fail to program a second time run
> their initially flashed program just fine, I just can't get at the
> JTAG port.
>
> I've searched the threads here and the LPC2194 errata and see
there
> are some programming problems with devices with early date codes.
> But that problems seems to be a lockup during programming, not
what
> I'm seeing. I've contacted Keils support vie email, I thought I'd
> try here also to see if anyone else has seen this...
>
> Any ideals, I'm stumped?

I'll post a answer to my own problem. Happens every time, I call
tech. support or post a question to a message list and I end up
answering my own question!!!

Anyaways, here is what I found:
I think I found a problem in Philip's LPC2194 data sheet. The
LPC2294 datasheet says that the JTAG pins (P1.26-P1.31) PINSEL
register is set to P1.26/RTCK at reset. The LPC2194 data sheet says
that the PINSEL register is set to '0' at reset. Reading that I
figured that I had to write a '1' to the JTAG PINSEL register to use
JTAG on the LPC2194. When I did that the JTAG port no longer
worked. If I take out the JTAG PINSEL init code I can program the
LPC2194 via JTAG. SO, I must assume that the LPC2194 works in the
same way as the LPC2294 and the data sheet for the LPC2194 is wrong.

Anyways, it works now...




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