Lpc2000

Hi Robert

It's a difficult sentence, I admit. What I wanted to say is that I 
used the Rx transceiver on the Kickstart Board (instead of the 
MAX202 on my board) to ensure that the Rx signal at the LPC2106 is 
really clean (I have read a lot about bad decoupling etc. at the 
transceivers leading to unreliability).

Of course I was testing previously directly with my board which uses 
a 5V MAX202 transceiver and with this test I wanted to see whether 
there was a difference using a 3V transceiver and also a known good 
RX path.

In fact the ISP utility is communicating with the Kickstart board 
and my board is simply listening in to the data received by the 
kickstart board. It responds and I compared its responses with those 
from the Kicksrat board. During an upload to the kick start board my 
board receives the same info and responds - the upload is successful 
since the responses seen at the ISP utility are from the Kickstart 
board which works perfectly. I monitor the responses from my board, 
which abruptly stop somewhere during the process.

This means that I am definitely sure that it's not a tranceiver 
problem.

In the mean time there is a little more information available:
- a second board shows identical symptoms and so it is a systematish 
problem with the hardware on my board.
- a friend of mine is also using the same chip in a different design 
(the chips he has are from the same batch as the ones on my boards, 
since we are working together on two pieces of equipment which 
communicate with each other). He confirms the problem with my board 
using his tools but has absolutely no difficulties with his 
hardware. We are using the same MAX202 circuitry (at 5V)..
- I am presently comparing in detail the differences between my 
hardware and his hardware - we both designed the two circuits in 
parallel and so obviously they are pretty much the same apart from 
the use of the ports. He uses only a few - all at 3.3V - but my 
design all of them, several at 5V level. Also the power suppy chips 
are identical with 2 x LM1117-ADJ for 3.3V and 1.8V and exactly the 
same voltage setting resistors.

This means that I will be spending my Saturday night stripping down 
my circuitry to an equivalent state as the other until it suddenly 
starts to work (I hope) - it should be a matter of time.

By the way, we both missed the fact that we loose 10 ports when 
using JTAG1 and both have the same problem with our hardware - they 
need redesigns if we want to use JTAG2 to get them back. Since we 
know JTAG well we didn't spend too much time considering the 
interface in great detail. JTAG1 worked well on the demo board and 
the ETM interface isn't of interest - the ETM mode of the ports is 
described as an alternative use in the Port section so that seemed 
to be flexible enough. In fact it takes quite detailed reading of 
the user manual to identify the fact that JTAG1 activation steals 10 
ports from you whether you like it or not. It would be a good idea 
for Philips to modify the document with a large warning - it would 
have saved us a lot of time and the boards reworks are not exacly 
cheap.

Hope to post a reason and cure soon.

Cheers

Mark Butcher


--- In lpc2000@yahoogroups.com, Robert Adsett <subscriptions@a...> 
wrote:
> Definitely check out James comments.  I've a few 
questions/comments myself.
> 
> At 10:50 PM 5/28/04 +0000, you wrote:
> >I have connected the Rx input (3.3V level from the Kickstart board
> >to the Rx input (directly at processor) on my board. The upload
> >still fails (it works on the Kickstart board, which is sending 
echos
> >and operating in parallel) but the Tx stops sometime during the
> >upload on mine [Tx obviously not connected to ISP utility - only 
for
> >monitoring]).
> 
> I've re-read this several times thinking I've read it wrong.  Let 
me see if 
> I've got this right.
> 
> - You have TX from the PC hooked up to RX on the kickstart board 
and RX on 
> your board.
> - You have RX on the PC hooked up to TX on the kickstart board.
> 
> Is this the only way you have tested it?
> 
> If you haven't run your board alone, I suggest you do so because 
the 
> symptoms you are reporting are exactly what I would expect from 
this 
> hookup.  As long as the micros don't have to do anything (or the 
kickstart 
> is slower than yours) they will stay in sync.  As soon as  your 
micro takes 
> longer than the kickstart to perform an operation it will receive 
a command 
> before it is ready for it and .....
> 
> Robert
> 
> " 'Freedom' has no meaning of itself.  There are always 
restrictions,
> be they legal, genetic, or physical.  If you don't believe me, try 
to
> chew a radio signal. "
> 
>                          Kelvin Throop, III