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From: Spehro Pefhany on 5 Mar 2010 17:29 On Fri, 5 Mar 2010 12:32:47 -0800 (PST), Chris <christopher.maness(a)gmail.com> wrote: >On Mar 5, 11:59�am, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: >> On a sunny day (Fri, 5 Mar 2010 11:11:38 -0800 (PST)) it happened Chris >> <christopher.man...(a)gmail.com> wrote in >> <29529065-09fc-4636-9a29-c618cbc16...(a)x1g2000prb.googlegroups.com>: >> >> >> >> >I have posted several threads about converting 24Hz pulses to 60Hz >> >basically a 5/2 ratio. �I tried a phase locked loop, it sorta works, >> >but my chip count is getting high, and I am thinking about making more >> >of these and selling them if I can write a computer program to resolve >> >wave sound files. >> >> >Therefore, since I am not very familiar with micro controllers, I was >> >not planning on using one. �However, I remember an engineer friend of >> >mine mentioning the BASIC stamp. �I have dabbled in BASIC so, I might >> >approach the problem with this as a solution, especially if I can do >> >it with one or two chips. >> >> >I would think that I could sample the 24Hz side for one second. �Take >> >that number and use it to divide a �much higher frequency quartz >> >reference by some large value of N so that I can get it back down to >> >60Hz. �Therefore my lock time would be one second. �I can have an easy >> >lock indication and a fairly fast response to any changes in >> >frequency. >> >> >What do you guys/gals think? >> >> >Regards, >> >Chris Maness >> >> Years ago I posted a PIC 50 Hz PLL asm code here. >> Or maybe it was 25 Hz. >> I would not bother with BASIC, likely way too slow, and way too much resources hungry. >> A 1$50 12 pin PIC should do... > >What are some models that would be good for that application. I see >some 8 pin models that are only $2. The only problem is that I have >NO clue how to start programming them. > >Regards, >Chris Just write code to initialize and make an LED flash at a visible rate. The rest is easy...
From: Jan Panteltje on 5 Mar 2010 17:43 On a sunny day (Fri, 05 Mar 2010 13:12:55 -0800) it happened Tim Wescott <tim(a)seemywebsite.now> wrote in <rKGdnSd76K6p6QzWnZ2dnUVZ_oYAAAAA(a)web-ster.com>: >> You DO need an oscilloscope in my opinion, else no clue what PIC does. >> >But then you need an oscilloscope for an analog PLL, or no clue what >it's doing. As we play with electrons, and those are so small we cannot see them, we will always need some instrument. A digital voltmeter on a PIC output does give a nice voltage depending on the duty cycle though. If you play with the PLL in the audio range, you can get a lot of info by feeding it into an amp. Even for higher frequencies by AC coupling the error voltage into an audio amp... etc etc. All tricks I have used. A 4046 makes a great audio FM modulator and demodulator too.
From: linnix on 5 Mar 2010 18:13 On Mar 5, 2:29 pm, Spehro Pefhany <speffS...(a)interlogDOTyou.knowwhat> wrote: > On Fri, 5 Mar 2010 12:32:47 -0800 (PST), Chris > > > > <christopher.man...(a)gmail.com> wrote: > >On Mar 5, 11:59 am, Jan Panteltje <pNaonStpealm...(a)yahoo.com> wrote: > >> On a sunny day (Fri, 5 Mar 2010 11:11:38 -0800 (PST)) it happened Chris > >> <christopher.man...(a)gmail.com> wrote in > >> <29529065-09fc-4636-9a29-c618cbc16...(a)x1g2000prb.googlegroups.com>: > > >> >I have posted several threads about converting 24Hz pulses to 60Hz > >> >basically a 5/2 ratio. I tried a phase locked loop, it sorta works, > >> >but my chip count is getting high, and I am thinking about making more > >> >of these and selling them if I can write a computer program to resolve > >> >wave sound files. > > >> >Therefore, since I am not very familiar with micro controllers, I was > >> >not planning on using one. However, I remember an engineer friend of > >> >mine mentioning the BASIC stamp. I have dabbled in BASIC so, I might > >> >approach the problem with this as a solution, especially if I can do > >> >it with one or two chips. > > >> >I would think that I could sample the 24Hz side for one second. Take > >> >that number and use it to divide a much higher frequency quartz > >> >reference by some large value of N so that I can get it back down to > >> >60Hz. Therefore my lock time would be one second. I can have an easy > >> >lock indication and a fairly fast response to any changes in > >> >frequency. > > >> >What do you guys/gals think? > > >> >Regards, > >> >Chris Maness > > >> Years ago I posted a PIC 50 Hz PLL asm code here. > >> Or maybe it was 25 Hz. > >> I would not bother with BASIC, likely way too slow, and way too much resources hungry. > >> A 1$50 12 pin PIC should do... > > >What are some models that would be good for that application. I see > >some 8 pin models that are only $2. The only problem is that I have > >NO clue how to start programming them. > > >Regards, > >Chris > > Just write code to initialize and make an LED flash at a visible rate. > The rest is easy... Or something like this: loop() { // sample 24Hz input now = ACSR & (1<<INPUT_BIT_NUMBER); // Analog comparator if(now && !before) // rising edge { // reload 60Hz timer TCCR1B = 3; // prescale by 64 n = 2083; // 8,000,000 / 64 / 60 TCNT1H = (n<<8)&0xff; TCNT1L = (n)&0xff; } before = now; } On_Timer1_Interrupt() { // pulse 60Hz output }
From: Chris on 5 Mar 2010 23:00 @linnix p.s. One more thing. I am really interested in what you did for your debounce. I was planning on using a NE555 in monostable mode for 20ms pulse to clean up the debounce. I was also planning on using a NE555 in mono for 60ms to latch and stay on as long as there is input into the converter box, but shut the loop down when there is no input. I do not want pulses going to the tape deck when the movie camera is not running. Regards, and thanks a ton all of you guys, Chris Maness
From: linnix on 5 Mar 2010 23:57
On Mar 5, 8:00 pm, Chris <christopher.man...(a)gmail.com> wrote: > @linnix > > p.s. > > One more thing. I am really interested in what you did for your > debounce. For debouncing, you can just wait a few msec after the loop, or just do some other processings. > I was planning on using a NE555 in monostable mode for 20ms > pulse to clean up the debounce. Atmel's PIC (Programmable IC) with crystal is far more accurate than the 555. > I was also planning on using a NE555 > in mono for 60ms to latch and stay on as long as there is input into > the converter box, but shut the loop down when there is no input. I > do not want pulses going to the tape deck when the movie camera is not > running. So, limit the timer interrupt free-running counts. Since you want a square output, use 120Hz timer interrupt. Revised code: loop() { // Analog comparator sample 24Hz input now = ACSR & (1<<INPUT_BIT_NUMBER); if(now && !before) // rising edge { // reload 120Hz timer TCCR1B = 3; // prescale by 64 n = 1541; // 8,000,000 / 64 / 120 TCNT1H = (n<<8)&0xff; TCNT1L = (n)&0xff; run = 0; // enable timer1 interrupt } before = now; } On_Timer1_Interrupt() { // toggle 60Hz output bit OUTPUT_PORT ^= (1<<OUTPUT_BIT_NUMBER); if(++run < 3) //enable timer1 interrupt } |