I have a sensor that outputs an analog signal (between 0 and 3.3v), and I need to know when that signal rises above a certain threshold voltage (the signal will be near 0 for a while, and then will suddenly rise). I haven’t decided on a threshold yet, but once I do it won’t change. Let’s just say it’s 1v for now.
Obviously I can use the Wixel’s ADC for this, but the ADC is a little too slow for me. Even on the lowest resolution (7 bits) it takes 20uS for an ADC read. I want to determine when the signal passes the threshold to within 10uS or better. I was thinking of using an analog comparator or something like this to give me a binary output, then reading that (a digital read should be fast enough). Is this necessary, or is there any way I can do this with a Wixel alone and no other hardware? Or better yet, how would you go about doing this?