----- Original Message ----- From: Olin Lathrop To: Sent: Wednesday, August 18, 2004 1:17 PM Subject: Re: [PIC:] Strange Jal error > Jason S wrote: > > It turns out I won't be using the 16F628 anyway. There's no ADC, > > which I didn't realize. Since I plan to use a 10-turn pot as the > > frequency control, I will need an ADC. > > So your plan is to run the output of the 10 turn pot into the PIC A/D? > Since the PIC A/D is 10 bit, you won't get anywhere near the resolution you > would expect from a 10 turn pot and an analog circuit. With a 10 bit A/D > you're only going to get 1024 different input settings. To put this another way: there are 360 degrees per turn and 10 turns. From end to end you will have to turn through 360*10 = 3600 degrees. Divide this by the range of the ADC which is 1024 and you get about 3.5 degrees per unit of ADC measurement. This meens you would have to turn the pot control by about 3.5 degrees before the ADC would register a change. Regards Sergio Masci -- http://www.piclist.com hint: To leave the PICList mailto:piclist-unsubscribe-request@mitvma.mit.edu