Lpc2000

I've been busy porting the TRAXMOD project from dsPICs to the LPC2103.

http://www.k9spud.com/traxmod/

Currently, it can play raw wave audio streaming off of a FAT formatted
MMC/SD Card at 44100Hz, 10-bits, stereo. It is also beginning to play
small 4 channel MOD music files. It uses the Embedded Filesytem
Library (EFSL) for the FAT filesystem support and is open source under
the GNU GPL.

It uses the LPC2103's PWM to as an output audio DAC. The circuitry is
very simple and should be easy for most LPC2103 users to build. I see
some questions about doing audio on LPC chips lately, maybe these
people can find something of use from this project.

---
K9spud Microcontroller Electronics
http://www.k9spud.com/

Em Seg 15 Mai 2006 06:52, Ed Schlunder escreveu:
> I've been busy porting the TRAXMOD project from dsPICs to the LPC2103.
>
> http://www.k9spud.com/traxmod/
>
> Currently, it can play raw wave audio streaming off of a FAT formatted
> MMC/SD Card at 44100Hz, 10-bits, stereo. It is also beginning to play
> small 4 channel MOD music files. It uses the Embedded Filesytem
> Library (EFSL) for the FAT filesystem support and is open source under
> the GNU GPL.
>
> It uses the LPC2103's PWM to as an output audio DAC. The circuitry is
> very simple and should be easy for most LPC2103 users to build. I see
> some questions about doing audio on LPC chips lately, maybe these
> people can find something of use from this project.

Just for curisity, how good is the audio generated by the PWM, sounds good, or 
when I want quality the way is to use a good DAC?

--- In lpc2000@yahoogroups.com, Xtian Xultz <xultz@...> wrote:

> Just for curisity, how good is the audio generated by the PWM,
sounds good, or 
> when I want quality the way is to use a good DAC?

Use a DAC if you can. The sound quality is decent with amplified
speakers. With earphones it is less than perfect because there is no
op-amp.

Unfortunately, most audio DACs require I2S input, which LPC2103 does
not have support for. They usually cost a lot too, you might pay more
for a DAC than the LPC2103 chip itself!

--- In lpc2000@yahoogroups.com, "Ed Schlunder" <zilym@...> wrote:
>
> --- In lpc2000@yahoogroups.com, Xtian Xultz <xultz@> wrote:
> 
> > Just for curisity, how good is the audio generated by the PWM,
> sounds good, or 
> > when I want quality the way is to use a good DAC?
> 
> Use a DAC if you can. The sound quality is decent with amplified
> speakers. With earphones it is less than perfect because there is no
> op-amp.
> 
> Unfortunately, most audio DACs require I2S input, which LPC2103 does
> not have support for. They usually cost a lot too, you might pay more
> for a DAC than the LPC2103 chip itself!
>

I built a project like this last summer: an LPC2106, a CF used as a
FAT32 disk drive and a VLSI VS1002d MP3 Decoder IC driving amplified
PC speakers.  See
http://www.sparkfun.com/commerce/advanced_search_result.php?keywords=vs1002&x=0&y=0
for the decoder.  My guess is that, in quantity, the price for the
decoder is much lower.

It certainly saves a lot of effort and delivers better results if you
just use a chip that has already been designed.

Richard.