DSPRelated.com
Forums

configuring codec so that fs=500Hz

Started by Marlo Flores May 9, 2002
Hi friends,

I program the c5402 in C language. I see in the codec
example that the sampling rates i can configure the
codec are only 2kHZ-16kHz using the available
function. How can I make the codec to sample at 500
Hz? Is there some other C-callable function which I
can use?

regards,
marlo



I've just read the manual (slas131e) of the tlc320ad50
codec (the codec on my dsk) and found out that

fs = MCLK/(512*N),

where MCLK is the master clock frequency=8.192 MHz, N
integer from 1 to 8. With these, I can only get back
to the same old sampling rates 2 kHz,...16kHz.

seems there's no other way...or is there?

marlo
--- Marlo Flores <> wrote:
> Hi friends,
>
> I program the c5402 in C language. I see in the
> codec
> example that the sampling rates i can configure the
> codec are only 2kHZ-16kHz using the available
> function. How can I make the codec to sample at 500
> Hz? Is there some other C-callable function which I
> can use?
>
> regards,
> marlo >
> _____________________________________
> Note: If you do a simple "reply" with your email
> client, only the author of this message will receive
> your answer. You need to do a "reply all" if you
> want your answer to be distributed to the entire
> group.
>
> _____________________________________
> About this discussion group:
>
> To Join: Send an email to > To Post: Send an email to
>
> To Leave: Send an email to > Archives: http://www.yahoogroups.com/group/c54x
>
> Other Groups: http://www.dsprelated.com > ">http://docs.yahoo.com/info/terms/


__________________________________________________



Dear all,
I am trying to implement code on TMS320VC5402 DSP
Starter's kit.(REV 0,100MHz DSP)
1)Like the memory map provided in
TMS320c54xDSK plus DSP Starter's KIT Users Guide,
(on page 26),

If I have vc5402 Chip on dsk board,where these
communications kernel,kernel buffer etc I mean monitor
programmes reside?
Does anybody have exact memory addresses?

2)If I select 6th DIP switch,OFF
in order to access Data memory onboard,
while running evmdsktest,it displays memory test
failed?
does this indicates there is no external memory?

3)if I select 2nd switch UP for Microprocessor,
evmdsktest fails at it's first stage of led blinking?

I could not get the memory map for this dsp starter
kit
(I got the memory map for VC5402 DSP chip,is it
equally applicable for kit?)

If anybody have solution,I am eagerly waiting for it.
Regards and thanks,
Manoj


Hello,

The answer is quite simple, as a matter of fact. A sample is no more
than a measurement of the voltage. The sample rate is the number of
times that this measurement is done during a second.

Now, if you want a sample rate of 500 Hz, but the codec gives you
only 2 kHz, all you have to do is to use one out of four samples. Let
the codec run at 2 kHz, and instead of reading every sample, you read
one, ignore the three after, and then read the next. And so on.

This will work 100% nice if you make sure that the input signal is
filtered so there are no signal above 250 Hz (simple Nyquist
theorem).

Good luck,

Eli

--- In c54x@y..., Marlo Flores <marlo_ti@y...> wrote:
> I've just read the manual (slas131e) of the tlc320ad50
> codec (the codec on my dsk) and found out that
>
> fs = MCLK/(512*N),
>
> where MCLK is the master clock frequency=8.192 MHz, N
> integer from 1 to 8. With these, I can only get back
> to the same old sampling rates 2 kHz,...16kHz.
>
> seems there's no other way...or is there?
>