Forums

clock freq. for new LPC2103

Started by Gus December 8, 2005
Anyone can help me in figuring out the best oscillator frequency to
run LPC2103 at the high speed (near 70Mhz) but keeping UART standard
baud rates? 9600 and 115200 for example

Gus


An Engineer's Guide to the LPC2100 Series

> Anyone can help me in figuring out the best oscillator frequency to
> run LPC2103 at the high speed (near 70Mhz) but keeping UART standard
> baud rates? 9600 and 115200 for example

The LPC2101/2/3 implement a fractional divider on the UARTs, just as in the
LPC214x series.

Enter in your peripheral clock and desired baud rate into my utility and it
will return a list sorted by margin of error:
http://groups.yahoo.com/group/lpc2000/files/Tools/lpc2fdcalc.exe

You should be able to run right at 70MHz and get nearly any baud rate you
like, at least on the UARTs... Joel


Gus,

I agree with Joel about the UART frequencies. To answer your question,
use a 10 MHz crystal, the only one that is within the PLL range 10-25
and that can generate the 70 MHz dead on.

Bob

--- In lpc2000@lpc2..., "Joel Winarske" <joelw@i...> wrote:
>
> > Anyone can help me in figuring out the best oscillator frequency to
> > run LPC2103 at the high speed (near 70Mhz) but keeping UART standard
> > baud rates? 9600 and 115200 for example
>
> The LPC2101/2/3 implement a fractional divider on the UARTs, just as
in the
> LPC214x series.
>
> Enter in your peripheral clock and desired baud rate into my utility
and it
> will return a list sorted by margin of error:
> http://groups.yahoo.com/group/lpc2000/files/Tools/lpc2fdcalc.exe
>
> You should be able to run right at 70MHz and get nearly any baud
rate you
> like, at least on the UARTs... > Joel
>