Lpc2000

You MUST enable the FIFO (by setting U0FCR:0) - See Description of 
that bit in Table 66 of LPC2106 User Manual.

Since other sections of the manual imply that you can run without 
this bit set, I asked Philips about it.  One of the apps engineers 
told me it was OK to run without the FIFO enabled.  Hwever, another 
apps engineer told me that the original intention was to allow 
operation without the FIFO, but they discovered some bugs operating 
in that mode, so they redefined the product to not allow that mode of 
operation.

So, as far as I know, if the FIFO is not enabled - all bets are off.

Robert: Are you also operating without the FIFO when you have your 
problems?

As to whether the problem operating without the FIFO (which Philips 
has long been aware of) might be caused by a similar race condition 
as the timer interrupt problem - interesting question.  When I 
discussed the FIFO issue with them, the timer problem had not yet 
been discovered.  Now that Philips has an understanding of the timer 
interrupt problem (and has reportedly implemented a fix on some new 
chips in development), their circuit designers should be able to 
easily determine if a similar problem exists here.

In fact, there are a number of other registers which also get written 
to by both the core and peripheral hardware.  Has Philips analyzed 
which of these are subject to the same problem with simultaneoues 
access?

Philips: How about letting us know what's going on!




--- In lpc2000@yahoogroups.com, "Leighton Rowe" <leightonsrowe@y...> 
wrote:
> 
> > >Should I enable the FIFOs (write 1 to U0FCR) before running the
> > >interrupts? I seem to be getting by without this up until this 
> point.
> > 
> > I don't see why that would eliminate the problem.  Worse it might 
> hide it 
> > so that it showed up later under less benign conditions.
> > 
> 
> Good news...I got communication running alot better after enabling 
> FIFOs (U0FCR = 1) at startup. So far, no Rx & Tx glitches yet. Try 
> doing the same to see what happens.
> 
> For now the LSR mystery is worth forgetting. 
> 
> 
> Leighton