Post by thread:freq meter

As I have had so many requests for the counter file I asked Bob Blick if he would put it on his site. This is his reply Bob Blick wrote: > > Hi Peter, > > Thanks, it looks like a good circuit. > > I put it at: > www.bobblick.com/bob/projects/freqlcd.zip Snip So anyone wanting this can download it from there at their convenience. Anyone wanting additional info contact me via private email -- Peter Cousens email: spam_OUTcousensTakeThisOuTher.forthnet.gr phone: + 3081 380534 snailmail: Folia, Agia Fotini, Karteros, Heraklion Crete, Greece. Is it true that they have, on the new version of windows managed to increase the MTBF from 95 to 98 minutes ? (That's why they called it 95)

Peter Cousens wrote: > http://www.bobblick.com/bob/projects/freqlcd.zip Hmm. Interesting. You are right, it is far easier to buy the kits of parts from Terry than trying to source them all, at least at a hobbyist level. It looks surprisingly complicated. It looks like the frequency stream is enabled and disabled by the chip. Wonder why? -- James Cameron (.....cameronKILLspam@spam@stl.dec.com) Digital Equipment Corporation (Australia) Pty. Ltd. A.C.N. 000 446 800

>It looks surprisingly complicated. It looks like the frequency stream >is enabled and disabled by the chip. Wonder why? Terry is doing a very interesting thing: the TMR0 input is rated to at least 50 MHz. By assigning the prescaler to TMR0, he can accumulate a number of counts in a given period in TMR0 and the prescaler. But the prescaler is not readable or writeable from within the pic. So - what he does is disable the external frequency input, store the TMR0 value somewhere, then generate and count his own pulses into the TMR0 input until TMR0 increments. Now he can figure out what the count was in the prescaler - that plus TMR0 gives him a 16 bit count value for gate time. Nice, simple, ingenious! dwayne Dwayne Reid <dwaynerKILLspamplanet.eon.net> Trinity Electronics Systems Ltd Edmonton, AB, CANADA (403) 489-3199 voice (403) 487-6397 fax

On Sun, 25 Oct 1998, Dwayne Reid wrote: > >It looks surprisingly complicated. It looks like the frequency stream > >is enabled and disabled by the chip. Wonder why? > > Terry is doing a very interesting thing: the TMR0 input is rated to at least > 50 MHz. By assigning the prescaler to TMR0, he can accumulate a number of > counts in a given period in TMR0 and the prescaler. But the prescaler is > not readable or writeable from within the pic. So - what he does is disable > the external frequency input, store the TMR0 value somewhere, then generate > and count his own pulses into the TMR0 input until TMR0 increments. Now he > can figure out what the count was in the prescaler - that plus TMR0 gives > him a 16 bit count value for gate time. Nice, simple, ingenious! And exactly as per a certain Microchip App not that's been around since 1995 at least. Ok, the printed version in the 1995 databook had some small mistakes but it was there. I think it was signed by M. DeSouza from Microchip.. Peter

> On Sun, 25 Oct 1998, Dwayne Reid wrote: snip > that plus TMR0 gives > > him a 16 bit count value for gate time. Nice, simple, ingenious! The counter diplays 7 digits, 16 bit is not enough It uses 24 bits AND Peter L. Peres wrote: > And exactly as per a certain Microchip App not that's been around since > 1995 at least. Ok, the printed version in the 1995 databook had some small > mistakes but it was there. I think it was signed by M. DeSouza from > Microchip.. I only made a couple of fixes and ported the code to 16x84 But the orignal article was published in November 1994 I am still getting request for the code/circuit so I will say again The code/circuit is available from Bob Blick's site www.bobblick.com/bob/projects/freqlcd.zip The hex, asm and circuit gif it's zipped and is 76K bytes And that the kit is availble from http://www.weedtech.com/ all parts including lcd and pcb for $46 (I think) -- Peter Cousens email: EraseMEcousensspam_OUTTakeThisOuTher.forthnet.gr phone: + 3081 380534 snailmail: Folia, Agia Fotini, Karteros, Heraklion Crete, Greece. Is it true that they have, on the new version of windows managed to increase the MTBF from 95 to 98 minutes ? (That's why they called it 95)