Need good quality Audio output through LPC21xx controller

<angaddhot@gmail.com> skrev i meddelandet 
news:ec7aa975-eed4-41df-9853-349749c08af8@m73g2000hsh.googlegroups.com...
On Sep 30, 11:00 pm, "Ulf Samuelsson" <u...@a-t-m-e-l.com> wrote:
> <angadd...@gmail.com> skrev i 
> meddelandetnews:0f148d36-bf58-48e7-9a34-1db113920ee2@v15g2000hsa.googlegroups.com...
> On Sep 30, 6:56 pm, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
> wrote:
>
>
>
> > angadd...@gmail.com wrote:
> > > We are working on a project based on Vehicle tracking system.In one of
> > > our module we are using audio(voice) for Public transport system.As
> > > if for now we are using filters and a power amplifer We are not able
> > > to get good quality audio output with this setup.
>
> > > Item used:
> > > Lpc2132 with MMC card interface ,High pass filter+ Low pass filter+
> > > Audio Amplifier+ Speaker
>
> > > Requirement:
>
> > > Good Voice quality annoucement system for Public transport System
>
> > With PWM at 32kHz carrier and 8bit quantization, you can get a
> > "telephone line" quality speech. It would be even better if you apply
> > the preemphasis and the noise shaping to the recorded signal. You can
> > gain somewhat more quality if you combine several PWM channels. However
> > if you need the "music" quality audio, you should use an external DAC.
>
> > Vladimir Vassilevsky
> > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
>
> What about DAC codec ??
> It needs I2S interface which is not available with LPC21XX.
> If anyone know how to convert SSP from microcontroller controller to
> I2S format in software.
>
> ==> There are plenty of controllers out there with I2S.
> The AVR32 based UC3A3 has SD-Card I/F,
> High speed USB, and I2S (as well as ADC/DAC)
> Should be considerably faster than the LPC as well.
>
> If you insist on ARM cores, then the AT91SAM7A3
> has SD-Card interface and I2S interface (SSC).
>
> --
> Best Regards,
> Ulf Samuelsson
> This is intended to be my personal opinion which may,
> or may not be shared by my employer Atmel Nordic AB

------------  > Its not possiable to change the controller ,I want to
know how can i convert SPI1 mode to I2S ,give me the code

You need to use a timer which generates the frame sync.
This is clocked from the SPI clock.
The SPI needs to transmit continuously, or you will have problem.
If that is not possible with the SPI block because
of internal delays on the SPI clock, then you need
to run the SPI in slave mode and generate the SPI clock from another timer.

If you do not have free timer resources, apply for a new job.

While waiting for a new job to appear, please write:
"Why are we so stupid that we selected the wrong controller."
on the blackboard 100 times.


-- 
Best Regards,
Ulf Samuelsson
This is intended to be my personal opinion which may,
or may not be shared by my employer Atmel Nordic AB 

angaddhot@gmail.com wrote:


> ------------  > Its not possiable to change the controller ,I want to
> know how can i convert SPI1 mode to I2S ,give me the code

Give me $700 bln.

VLV

On Sep 30, 8:40 am, angadd...@gmail.com wrote:
> On Sep 30, 6:56 pm, Vladimir Vassilevsky <antispam_bo...@hotmail.com>
> wrote:
>
>
>
> > angadd...@gmail.com wrote:
> > > We are working on a project based on Vehicle tracking system.In one of
> > > our module we are using audio(voice)  for Public transport  system.As
> > > if for now we are using  filters and a power amplifer We are not able
> > > to get good quality audio output with this setup.
>
> > > Item used:
> > > Lpc2132 with MMC card interface ,High pass filter+ Low pass filter+
> > > Audio Amplifier+ Speaker
>
> > > Requirement:
>
> > > Good Voice quality annoucement system for Public transport System
>
> > With PWM at 32kHz carrier and 8bit quantization, you can get a
> > "telephone line" quality speech. It would be even better if you apply
> > the preemphasis and the noise shaping to the recorded signal. You can
> > gain somewhat more quality if you combine several PWM channels. However
> > if you need the "music" quality audio, you should use an external DAC.
>
> > Vladimir Vassilevsky
> > DSP and Mixed Signal Design Consultanthttp://www.abvolt.com
>
> What about DAC codec ??
> It needs I2S interface which is not available with LPC21XX.
> If anyone know how to convert SSP from microcontroller controller to
> I2S format in software.

SSP is the coding/decoding format and I2S is the transfer protocol,
right?  Let me re-phase it, can you convert MP3 into USB?

Op Wed, 01 Oct 2008 18:15:28 +0200 schreef Vladimir Vassilevsky  
<antispam_bogus@hotmail.com>:
> angaddhot@gmail.com wrote:
>> ------------  > Its not possiable to change the controller ,I want to
>> know how can i convert SPI1 mode to I2S ,give me the code
>
> Give me $700 bln.

I'll do it two times faster for half the price!


-- 
Gemaakt met Opera's revolutionaire e-mailprogramma:  
http://www.opera.com/mail/