Lpc2000

--- In lpc2000@yahoogroups.com, "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...