Author Topic: counter required to count to near 1 million  (Read 23076 times)

0 Members and 1 Guest are viewing this topic.

Offline marmad

  • Super Contributor
  • ***
  • Posts: 2979
  • Country: aq
    • DaysAlive
Re: counter required to count to near 1 million
« Reply #100 on: March 30, 2013, 10:18:50 am »
@Simon - Here's a nice webpage about the Pierce oscillator and choosing values for the various components. You'll want to use the second schematic from the top that includes the output buffer.
 

Offline marmad

  • Super Contributor
  • ***
  • Posts: 2979
  • Country: aq
    • DaysAlive
Re: counter required to count to near 1 million
« Reply #101 on: March 30, 2013, 11:05:04 am »
I'll use a set of nots then or maybe nands, I'll see what is cheaper and stock up. What is a good series of chips these days, I guess a CD4000 does not actually exist any more.

If you don't need supply voltages above 5V, I think the 74HC04 is about as cheap as they come - but it's been awhile since I bought them.

Also, an interesting Fairchild application note on CMOS oscillators.
« Last Edit: March 30, 2013, 11:14:04 am by marmad »
 

Offline Simon

  • Global Moderator
  • *****
  • Posts: 14762
  • Country: gb
  • Did that just blow up? No? might work after all !!
    • Simon's Electronics
Re: counter required to count to near 1 million
« Reply #102 on: April 06, 2013, 09:34:46 am »
Well I tried a single gate clock gen and it works on, I get a clean-ish signal but my output from the whole lots is still bursting all over the place. Oddly I notice that it seems associated with sounds perhaps.

I've now setup with one channel on the clock, and one on the final output, the clock is fine, the output responds to sound levels from my speakers possibly of particular frequencies. At first I thought the crystal was acting as a mic but the clock it is producing is clean.
 

Offline marmad

  • Super Contributor
  • ***
  • Posts: 2979
  • Country: aq
    • DaysAlive
Re: counter required to count to near 1 million
« Reply #103 on: April 06, 2013, 10:26:19 am »
I've now setup with one channel on the clock, and one on the final output, the clock is fine, the output responds to sound levels from my speakers possibly of particular frequencies. At first I thought the crystal was acting as a mic but the clock it is producing is clean.

Well, this is not how CMOS gates act normally; they're usually very stable. It seems to me it has to be a power supply problem; unused/untied/incorrectly wired input; or a breadboard specific problem. Use your DSO to check each input and output against the datasheets to make sure they're at the correct levels.

Is your power supply clean? What voltage are you running the circuit at?
« Last Edit: April 06, 2013, 10:31:40 am by marmad »
 

Offline Simon

  • Global Moderator
  • *****
  • Posts: 14762
  • Country: gb
  • Did that just blow up? No? might work after all !!
    • Simon's Electronics
Re: counter required to count to near 1 million
« Reply #104 on: April 06, 2013, 10:42:48 am »
I've got it running off a 5V regulator, I'm wondering if it's pickup between wires as my breadboard looks like transmission central. I think I'll try veroboarding it and see if it settles down.

I need to get a smidtt gate and hopefully the pulse generator works on it.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf