I'm assuming your device will have a digital display, for feedback? What's wrong, with the "classic" frequency generator UI? Sent from my phone > On Jul 18, 2014, at 6:17, David C Brown wrote: >=20 > I am building a simple pulse generator using an LTC6903 "synthesiser chip= " > and a few TTL chips. The range will be from about 0.1Hz to 68MHz and the > 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, non > of them entirely satisfactory, but I would appreciate, in the first > instance, suggestions which are not influenced by my thinking. > --=20 > __________________________________________ > David C Brown > 43 Bings Road > Whaley Bridge > High Peak Phone: 01663 733236 > Derbyshire eMail: dcb.home@gmail.com > SK23 7ND web: www.bings-knowle.co.uk/dcb > > --=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 .