adc sampling frequency

Started by omprakash alone September 2, 2010
Hi,
I am using LPC2148 ARM Controller having 2 adc(6 + 8 channels) and one dac channel.

My ADC is having sampling frequency of 410 ksps ad dac of 400 ksps.

but i want both adc should work on max of 500 Hz.

For setting sampling frequency of adc/dac ie 500 Hz, what i have to do?

Omprakash Alone

An Engineer's Guide to the LPC2100 Series

I hope you are familiar with the concept of timer interrupts. If not, then
you need to read that up.

Once you have your timer interrupts working, you can do any chosen task in
the ISR, provided it is not consume a lot of CPU time.

In the case of ADC conversions, the time taken is significant. My
suggestion is that the timer ISR (at 500 Hz) should trigger the conversion
and exit. This could mean several things: The ISR could set a flag and
exit, which is then polled in your main routine to cause a start of
conversion. Or, the ISR could start the conversion and exit, with a
End-of-Conversion interrupt signalling you when to read the value.

Just out of curiosity, what is your electronics background? Or are you a
software applications engineer trying your hand at embedded electronics?

On Thu, Sep 2, 2010 at 9:47 AM, omprakash alone wrote:

> Hi,
> I am using LPC2148 ARM Controller having 2 adc(6 + 8 channels) and one dac
> channel.
>
> My ADC is having sampling frequency of 410 ksps ad dac of 400 ksps.
>
> but i want both adc should work on max of 500 Hz.
>
> For setting sampling frequency of adc/dac ie 500 Hz, what i have to do?
>
> Omprakash Alone
>
>
>