Hi,
I discovered that I judged the issue in hurry. The nxp calculator is wrong
(does not match with data shown in the lpc2148 user manual)
I tried more baud rates and found that testing all combinations is a must
However, I discovered another exception as specified here
http://www.embeddedrelated.com/groups/lpc2000/show/22924.php by Karl Olsen.
Manuals of newer chips like 236x say that DL should be >= 2 as it makes
problems in higher baud rates
I modified my
calcand
it works very well now. I upload it in files section
Best Regards,
Karim A. Emara
On Mon, Mar 8, 2010 at 5:17 PM, Karim Emara wrote:
> Hi,
>
> I am working with LPC2148 and trying to figure out how optimal baud rate is
> computed for UART0. I tried to make an excel file to tryout all
combinations
> and get the optimal values of (MulVal, DIVADDVAL and DL). However, optimal
> values are not the same shown in the user manual. I searched for similar
> calculators and found this calculator on nxp
>
>
http://www.standardics.nxp.com/support/documents/microcontrollers/xls/lpc2000.uart.baudrate.calculator.xls
>
> It works in the same manner/equations i used in my calc but the only
> difference is the values range of MulVal and DivAddVal. It uses 0
> <= DivAddVal <= 14 while it uses DivAddVal < MulVal <= 15 !!! In manual, it
> asserts that both ranges are from 0 - 15 (except that MULval is nonzero)
>
> After using such ranges in my calc, results are exactly the same as shown
> in the user manual. Does anyone know why these ranges are selected?
>
> Thanks in advance
>
> Best Regards,
> Karim A. Emara
>