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fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
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Posted: Sun Apr 27, 2008 11:57 pm Post subject:
Load Pattern Issue Subject description: everything works fine exept... |
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as you might know, i almost finished the klee last week, i just did not wire the scale selector at all, yet.
everything worked fine from the start, except the pattern load functionality.
here is the story: on day one it did not work like expected. on day two i read the instructions (know your klee) and tried again. it worked. on day three it did not work again!?
(i set the klee to the common 1x16 pattern, no random setting)
the issue: when i push the load button nothing happens, until a clock signal appears, then the pattern is loaded but the klee stops running. it stucks until the load button is pushed again!
it does not matter if i use the manual switch, external signal or bus1 to load the pattern. i always need to "load, clock, load".
what really annoys me is the "it didn't work, then it did, now it doesn't"-story...
should i try another CD4071? _________________
cheers,
matthias
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Big Boss at fonitronik
Tech Buddy at Random*Source |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Mon Apr 28, 2008 4:24 am Post subject:
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Hi Fonik,
After you power the Klee up, press LOAD pushbutton then check U5- pins 1 and 13 on page 2 of the digital schematic. They should both be 0V, or logic low. This is important as this FF, wired as a mono-stable or one-shot, provides some critical control to the CD4034 shift registers.
If this is not the case, check the components around this CD4013 IC. R21, D3, C9, set the width of the pulse. C10, R20 and one section of U2 inverter are used to provide a RESET pulse to the first FF section (Drives U5-1 low).
Bill |
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Scott Stites
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Joined: Dec 23, 2005 Posts: 4127 Location: Mount Hope, KS USA
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Posted: Mon Apr 28, 2008 6:58 am Post subject:
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Yep - what Bill said.
Also, to eliminate any problems leading up to that (IE with the load switch/circuitry), when the problem occurs, try using an external pulse - just put a slow LFO into the external load and see if it works where the load switch doesn't.
If all else fails, you might also try subbing in another CD4013 (if you have one handy).
Cheers,
Scott _________________ My Site |
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fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
Audio files: 23
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Posted: Mon Apr 28, 2008 7:49 am Post subject:
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thanks for that, boys. will try that today or tomorrow.
State Machine wrote: | Hi Fonik,
After you power the Klee up, press LOAD pushbutton then check U5- pins 1 and 13 on page 2 of the digital schematic. They should both be 0V, or logic low. |
while pressed or when pressed once? _________________
cheers,
matthias
____________
Big Boss at fonitronik
Tech Buddy at Random*Source |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Mon Apr 28, 2008 8:07 am Post subject:
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Quote: | while pressed or when pressed once? |
Press LOAD, then check the logic levels.
Bill |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Mon Apr 28, 2008 9:20 am Post subject:
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It sounds as though the second section of the 4013 FF is not going high (U5-13). This is the shift register synchronous/asynchronous control input. Each time you press the LOAD button, the fist half of the FF toggles (U5-1). The first LOAD will make U5-1 logic high, and if U5-13 remains low, the CD4034 is in synchronous parallel mode which explains why the shift registers load when the clock comes along, but, since now you stuck in this mode, the shift registers never advance with each new clock. The registers just keep getting loaded. Then, when you press LOAD again, the flip-flop toggles and U5-1 goes back low. This is now the synchronous, serial data mode and the Klee will work normally.
Like Scott says, with a clock feeding the LOAD external input, you might want to see if the 4013 outputs (U5-1, and U5-13) are pulsing at around 20 to 30 uS each rising edge of the LOAD input. If U5-1 is toggling every other LOAD, then there is a definite problem. The stable state of this FF should be logic low when wired in the configuration that Scott has it in. This is a rather unusual application so some study of it's operation may be required but it becomes very clear how it operates.
Consulting the CD4034 data sheets truth table for this device should reveal how this all is working. It will all make sense once you see the truth table.
Bill
Bill |
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fonik
Joined: Jun 07, 2006 Posts: 3950 Location: Germany
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Posted: Mon Apr 28, 2008 11:27 pm Post subject:
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State Machine wrote: | It sounds as though the second section of the 4013 FF is not going high (U5-13). |
that's it, bill. thanks. you were right. wanted to replace the 4013 yesterday and i realized that pin13 (IIRC?) was bent under the IC and had no constant contact to the socket! now everything is working quite fine and i had a lot of fun yesterday, even without the scaler!
again, thank you bill & scott for taking care. _________________
cheers,
matthias
____________
Big Boss at fonitronik
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Tue Apr 29, 2008 4:08 am Post subject:
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Quote: | hat's it, bill. thanks. you were right. wanted to replace the 4013 yesterday and i realized that pin13 (IIRC?) was bent under the IC and had no constant contact to the socket! now everything is working quite fine and i had a lot of fun yesterday, even without the scal |
Great news ...
Glad to help !
Bill
PS: Your panel is one of the pictures I had shown at Analog Heaven North East demonstration last Saturday . |
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