Lpc2000

1.7% means that the 11th bit of each character is off by about 20% 
(1.017 ^ 11).  This is not unusable given that my signals are clean. 
Still, your expectations may be right for many UARTs in noisy
environments.  I really don't know what most software UARTS do.  What
I do know is that the 1.7% is irrelevant because the chip performs
inconsistently given the same baudrate.

The experiment I detailed was chosen to point out how the same
baudrate performs differently based on register settings.  

Furthermore, my initial issue utilized a 500,000 baudrate exactly and
still didn't work.  Only when I doubled the PCLK so that my U1DLL
could be 0x02 instead of 0x01 did the system start operating correctly.

JP

--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
>
> jp_thrower wrote:
> 
> >The baud rate may be off by 1.7 %, however the PC still communicated
> >correctly when I used the exact same baud rate, 117187, from other
> >register configurations (as reported U1DLL= 0x02, 0x03).  
> >
> >  
> >
> I thought that the acceptable degree of error is somewhere around
0.5%?  
> 1.7% seems to be very high...
> 
> Let's see, 2400 - 1.7% == 2359buad, nope, I would not expect that to 
> work!  I've gotten errors while being as much as 10 points of at 2400, 
> e.g. 2390baud.
> 
> Where do you see that a 1.7% deviation is acceptable?  It has been a 
> while since I've played with software uarts but I tried to keep within 
> 0.25% of error.
> 
> 
> TomW
> 
>