Forums

FTDI's new FT232R as clock source

Started by Aryeh Eiderman December 24, 2005
Hi,

The new USB-to-UART chip from FTDI - FT232R -
have now all the features of SiLabs' CP210X
and one additional feature: 6/12/24/48 MHz
clock to drive an external microcontroller.

So my questions are:

1. Is this clock can be used on LPC2000 instead
of crystal?
2. If yes, how to connect it to LPC2000? To
leave XOUT of LPC2000 unconnected?

Thank You,

Aryeh


An Engineer's Guide to the LPC2100 Series

> 1. Is this clock can be used on LPC2000 instead
> of crystal?
> 2. If yes, how to connect it to LPC2000? To
> leave XOUT of LPC2000 unconnected?

Excerpt from LPC214x manual:

"While an input signal of 50-50 duty cycle within a frequency range from
1MHz to 50MHz can be used by the LPC2141/2/4/6/8 if supplied to its input
XTAL1 pin, this microcontrollers onboard oscillator circuit supports
external crystals in the range of 1MHz to 30MHz only. If the on-chip PLL
system or the boot-loader is used, the input clock frequency is limited to
an exclusive range of 10MHz to 25MHz."

It may vary depending on your choice of MCU, so check the particular MCU
user manual under the "Crystal Oscillator" section. Joel


Thank You Joel!

I am using LPC2106.
In manual looks like the 214x but less described...
--- In lpc2000@lpc2..., "Joel Winarske" <joelw@i...> wrote:
>
> > 1. Is this clock can be used on LPC2000 instead
> > of crystal?
> > 2. If yes, how to connect it to LPC2000? To
> > leave XOUT of LPC2000 unconnected?
>
> Excerpt from LPC214x manual:
>
> "While an input signal of 50-50 duty cycle within a frequency range
from
> 1MHz to 50MHz can be used by the LPC2141/2/4/6/8 if supplied to
its input
> XTAL1 pin, this microcontroller's onboard oscillator circuit
supports
> external crystals in the range of 1MHz to 30MHz only. If the on-
chip PLL
> system or the boot-loader is used, the input clock frequency is
limited to
> an exclusive range of 10MHz to 25MHz."
>
> It may vary depending on your choice of MCU, so check the
particular MCU
> user manual under the "Crystal Oscillator" section. > Joel
>