Propeller Question...

xnederlandx

Hi,

I've read the manuals etc. it says something about Analog to Digital Conversion (CTRA/CTRB ?), but not in much detail


Can the propeller do Analog to Digital Conversion, and If so how many bit is it?

Would you have any coding examples (for Spin)?

Thanks in advance.

Post Edited (xnederlandx) : 6/7/2008 9:28:40 AM GMT

Graham Stabler

ADC can be done using a process called delta sigma conversion:

en.wikipedia.org/wiki/Delta-sigma_modulation

Chip shows an example here of both ADC and DAC.

http://forums.parallax.com/showthread.php?p=576575

Taken from my thread index which you may find helpful:

http://forums.parallax.com/showthread.php?p=609066

Graham

xnederlandx

Thankyou very much

xnederlandx

Hi

Thanks again for that, I read your SPIN EXAMPLES for BEGINNERS GUIDE, its great and has taught me a lot !

I have a 12bit ADC In...

I've been looking at Objects with floating point (?) calculation but they're all so complex to me...
How can I find the square root of the 16bit ADC in (with decimal)?

Sorry for asking so many questions... [noparse]:([/noparse] I'm new to the propeller and the SPIN language.

Thanks again.

Post Edited (xnederlandx) : 6/7/2008 8:20:41 AM GMT

Mike Green

There is an integer square root operator. If you want the square root to 1 decimal place (as a scaled integer), you'd do:

result := ^^( ADCvalue * 100)

If you want the square root to 2 decimal places (as a scaled integer), you'd do:

result := ^^( ADCvalue * 10000)

Similarly, three decimal places would be:

result := ^^( ADCvalue * 1000000)

Note that this last case will only work for a 12 bit ADC value because of overflow of the 32 bit intermediate result

xnederlandx

Thanks again!