Lpc2000

Alex,
No, I do not connect the codec to the micro.  The primary function of 
my project is to pass audio.  And I do use a codec and a DSP.  

The codec must have a 12.288MHz clock to generate the bit and frame 
clocks for 24-bit 48kHz sampled audio.  Since I have to have this 
clock anyway, why not use it for the 2131 as well?  It saves me some 
money and works fine.  I am still able to use the UART for 
communications and I also use I2C, SPI, PWM without a problem at this 
frequency (actually the PLL is set up for M=4 ==> 49.152MHz)

Dave

--- In lpc2000@yahoogroups.com, Alex_Rambler <bor-alex@r...> wrote:
>
> Hi Dave B
> 
> Why do you use 12.288MHz clock? Do you connect audio codec to 
LPC2131?
> 
> d> Hi Marcio,
> d> Yes, that mode of operation is supported.  I have been running a 
> d> LPC2131 with an external 12.288MHz clock that is buffered and 
feeds 
> d> everything on my board.  Works fine.
> 
> d> See page 31/32 of the manual.  There is some info there although 
I 
> d> agree it is not very clear.  Just leave the unused pin 61 
(XTAL2) 
> d> open.  Also, make sure you use the recommended (100pF) coupling 
cap 
> d> for XTAL1.
> d> See figure 7a for slave mode.
> 
> d> Good Luck,
> d> Dave B.
>