3 ms·
You could also just feed a ramping pwm output to a lowpass filter and have it go into a comparator, with the other input to the comparator be the analog signal
by aswanson 18y ago
You could also just feed a ramping pwm output to a lowpass filter and have it go into a comparator, with the other input to the comparator be the analog signal to be measured. You watch the pwm count and when the comparator fires, you have the digitized signal in the pwm count.
- kragen 18y agoRight, and this sweet little chip already has the PWM output and the analog comparator, and you can get a wakeup interrupt from the comparator. And then there's the VFC/VCO approach someone else suggested. But I think you can get a higher sample rate with a dedicated ADC. How fast can you do the PWM/comparator trick on a device like this?
- aswanson 18y agoYou can always get a higher rate with a dedicated chip, and they are pretty cheap these days. The max you can do the pwm trick is a function of the max clock rate, divide down pwm clock, and the number of bits you want for resolution. Take a look here: http://www.designingwithsensors.com/applications/all_articles.php?art_id=783 http://www.designingwithsensors.com/applications/all_article...