Post by thread:Help needed with 4 Mhz clock oscillator

Donald, you can use almost any crystal up to 20 Mhz using different then what originally you need will effect on speed only you need to adjust your delay routine. you do not have to use any crystal eider use RC. you can also use your signal generator as well make sure you have sign wave or can based oscillator. Andre. Donald Kihenja wrote: > Hi there,I am new to design with the PIC. I am about to present a > class LED driving demo using a PIC 16F84. I recently ordered my parts > but realised I forgot to order the 4Mhz clock oscillator. I don't have > enough time (three days) to wait for a mail ordered oscillator. Can I > use a 4 Mhz signal from a signal generator instead. Any other > alternatives? CoardiallyDonald.

This is actually an interesting question. Does it have to be a sine wave like a xtal's? Or will a square wave work? Description for the OSC1/CLKIN pin is: "Oscillator crystal input/external clock source input" Anybody used a squarewave or any other logic clock source? Quentin Andre Abelian wrote: you can also use your signal generator as well > make sure you have sign wave or can based oscillator. > Donald Kihenja wrote: Can I > > use a 4 Mhz signal from a signal generator instead. Any other > > alternatives?

> This is actually an interesting question. > Does it have to be a sine wave like a xtal's? Or will a square wave > work? Works fine. Check the spec though, for levels, rise and fall times, and duty-cycle. Old trick on the Z-80 was to run it on an asymmetrical clock, which let you speed it up quite a bit beyond it's max with a 50% duty cycle clock.

> > This is a multi-part message in MIME format. > > ------=_NextPart_000_0079_01BE9558.1E54FEE0 > Content-Type: text/plain; > charset="iso-8859-1" > Content-Transfer-Encoding: quoted-printable > > Hi there, > I am new to design with the PIC. I am about to present a class LED = > driving demo using a PIC 16F84. I recently ordered my parts but realised = > I forgot to order the 4Mhz clock oscillator. I don't have enough time = > (three days) to wait for a mail ordered oscillator. Can I use a 4 Mhz = > signal from a signal generator instead. Any other alternatives? Where are you? Go down to RatShack and buy a 3.58 Mhz colorburst crystal. It'll run a little slower, but should be just fine. BAJ

> >Where are you? Go down to RatShack and buy a 3.58 Mhz colorburst crystal. >It'll run a little slower, but should be just fine. > >BAJ > The Radio Shack color burst crystal is a special order.....not stocked.

> > > > >Where are you? Go down to RatShack and buy a 3.58 Mhz colorburst crystal. > >It'll run a little slower, but should be just fine. > > > >BAJ > > > > > The Radio Shack color burst crystal is a special order.....not stocked. > I hate that RatShack no longer carries stuff like that in store. The strange thing is that they do stock a whole bunch of 74HTC type logic. One day I'll grow up and understand their practices. Bummer. BAJ