Lpc2000

Don't forget the joys of over sampling.

The 2138 DAC has a settling time of 1 usec. You could put out data at the rate of 500Khz with over sampling and a simple finite impulse response filter this would extend the 10 bit DAC to the equivalent of 13 Bits resolution.

Some of the early cd players used to do this. They had an oversampled 14 bit DAC with FIR. The result has noticely less phase distortion than a 16 bit DAC with filters for 44Khz  

Owen Mooney 




--- In lpc2000@yahoogroups.com, Andreas Schwarz <usenet@a...> wrote:

>> Hi,
>> 
>> I have a software MP3 decoder running in my LPC2106, but I'm still 
>> looking wor a way to interface an audio DAC. I2S seems to be 
>  
>
impossible 

>> to implement without expensive additional hardware (CPLD/FPGA), and 
>  
>
I 

>> didn't find any DACs with SPI, except for the VS10xx (which would 
>  
>
be 

>> kind of stupid for a software MP3 decoder).
>> 
>> Any ideas?
>> 
>> Thanks
>> Andreas
>  
>

Maybe not the answer you were looking for, but the 10 bit DAC on the 
2138 does this reasonably well. The Keil development board and 
software has an MP3 and some other audio demos.

Tom





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