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
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> chew a radio signal. "
>
> Kelvin Throop, III