This type of device behavior would cause what UI designers call "user aston= ishment". Sent from my phone > On Jul 18, 2014, at 7:51, Kerry wrote: >=20 > One way I have thought about (but have not tried yet) is to use a=20 > mechanical encoder. > Step by 1s. If you see 10 steps in the same direction, start stepping=20 > by 10s. > If you see 10 steps of 10 in the same direction, start stepping by 100s. > If you see 10 steps of 100 in the same direction, start stepping by 1000s= .. > If you see a step in the opposite direction, go back to stepping by 1s. > I don't know if this would be more of a PITA than it's worth. > An alternative would be to measure the time between encoder pulses, and=20 > take bigger steps for quicker pulses. >=20 > Kerry >=20 >=20 >> On 7/18/2014 8:17 AM, David C Brown wrote: >> I am building a simple pulse generator using an LTC6903 "synthesiser chi= p" >> and a few TTL chips. The range will be from about 0.1Hz to 68MHz and th= e >> frequency is set, geometrically, by a 15 bit control word. I will be >> using a PIC16F87 to control the synthesiser and drive a display. >>=20 >> My problem is how to set the frequency by hand using the minimum panel >> hardware. I need control at the finest level, stepping the control >> register by one but also need to be able to make large frequency shifts >> quickly, perhaps stepping the register by 2^10 >>=20 >> I have studied this for some time and come up with several solutions, no= n >> of them entirely satisfactory, but I would appreciate, in the first >> instance, suggestions which are not influenced by my thinking. >=20 > --=20 > http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .