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Sci.Electronics.Basics -> Probably a stupid question...
There are 5 messages in this thread.
You are currently looking at messages 1 to 5.
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Author: DaveDate: 22:05 05-08-08
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Trying to use a (Motorola) MC14017 to drive a circuit to step through a
series of configurations, only I can't seem to be able to get it to *count*.
I have pin 16 connected to +5V, the clock running off of the Q output of a
4027 J/K flip-flop, pin 13 (clock enable) hooked to +5V, and pin 7 (decoded
3 output) set to hit pin 15 (reset) with a logic 1 when the device counts
that high. Only it doesn't count. If I unhook pin 7/15 then pin 3 (decoded
0) goes high and stays there. Hook pin 7/15 back up, and the device seems
to go dead. Pin 3 (decoded 0) never goes high again. At my wit's end.
Anyone have any idea what I might be doing wrong? Have replaced the chip 3
times, with no differing result. Oh, and pin 8 is grounded. Would love for
someone to point out just how dumb I am at this point...
Thanks,
Dave
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Author: BobWDate: 22:21 05-08-08
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"Dave" <db5151@hotmail.com> wrote in message
news:84OdnZa9C4OTmgTVnZ2dnUVZ_rfinZ2d@posted.internetamerica...
> Trying to use a (Motorola) MC14017 to drive a circuit to step through a
> series of configurations, only I can't seem to be able to get it to
> *count*. I have pin 16 connected to +5V, the clock running off of the Q
> output of a 4027 J/K flip-flop, pin 13 (clock enable) hooked to +5V, and
> pin 7 (decoded 3 output) set to hit pin 15 (reset) with a logic 1 when the
> device counts that high. Only it doesn't count. If I unhook pin 7/15
> then pin 3 (decoded 0) goes high and stays there. Hook pin 7/15 back up,
> and the device seems to go dead. Pin 3 (decoded 0) never goes high again.
> At my wit's end. Anyone have any idea what I might be doing wrong? Have
> replaced the chip 3 times, with no differing result. Oh, and pin 8 is
> grounded. Would love for someone to point out just how dumb I am at this
> point...
>
> Thanks,
>
> Dave
>
The MC14017 datasheet I'm looking at says that pin 13 is an active low clock
enable. Assuming that this is correct, you need to tie pin 13 low to enable
its clock.
Bob
--
== All google group posts are automatically deleted due to spam ==
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Author: John PopelishDate: 22:25 05-08-08
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Dave wrote:
> Trying to use a (Motorola) MC14017 to drive a circuit to step through a
> series of configurations, only I can't seem to be able to get it to *count*.
> I have pin 16 connected to +5V, the clock running off of the Q output of a
> 4027 J/K flip-flop, pin 13 (clock enable) hooked to +5V, and pin 7 (decoded
> 3 output) set to hit pin 15 (reset) with a logic 1 when the device counts
> that high. Only it doesn't count. If I unhook pin 7/15 then pin 3 (decoded
> 0) goes high and stays there. Hook pin 7/15 back up, and the device seems
> to go dead. Pin 3 (decoded 0) never goes high again. At my wit's end.
> Anyone have any idea what I might be doing wrong? Have replaced the chip 3
> times, with no differing result. Oh, and pin 8 is grounded. Would love for
> someone to point out just how dumb I am at this point...
When the decode 3 output is connected to the reset, it stays
high only as long as it takes for the reset to propagate
through the chip. Are you able to see a fraction of a
microsecond high on pin 7 with the equipment you are using?
What do you connect to pin 15 when pin 7 is not connected to it?
--
Regards,
John Popelish
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Author: DaveDate: 22:32 05-08-08
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"BobW" <nimby_GIMME_SOME_SPAM@roadrunner.com> wrote in message
news:M6WdndBtiMW2lgTVnZ2dnUVZ_rTinZ2d@giganews.com...
>
>
>
>
> "Dave" <db5151@hotmail.com> wrote in message
> news:84OdnZa9C4OTmgTVnZ2dnUVZ_rfinZ2d@posted.internetamerica...
>> Trying to use a (Motorola) MC14017 to drive a circuit to step through a
>> series of configurations, only I can't seem to be able to get it to
>> *count*. I have pin 16 connected to +5V, the clock running off of the Q
>> output of a 4027 J/K flip-flop, pin 13 (clock enable) hooked to +5V, and
>> pin 7 (decoded 3 output) set to hit pin 15 (reset) with a logic 1 when
>> the device counts that high. Only it doesn't count. If I unhook pin
>> 7/15 then pin 3 (decoded 0) goes high and stays there. Hook pin 7/15
>> back up, and the device seems to go dead. Pin 3 (decoded 0) never goes
>> high again. At my wit's end. Anyone have any idea what I might be doing
>> wrong? Have replaced the chip 3 times, with no differing result. Oh,
>> and pin 8 is grounded. Would love for someone to point out just how dumb
>> I am at this point...
>>
>> Thanks,
>>
>> Dave
>>
>
> The MC14017 datasheet I'm looking at says that pin 13 is an active low
> clock enable. Assuming that this is correct, you need to tie pin 13 low to
> enable its clock.
>
> Bob
> --
> == All google group posts are automatically deleted due to spam ==
>
Bedamned. That was it. Laughing now. Got my wish...
Thank you. Seriously. I just missed that. Don't ask me how...
Take it easy...
Dave
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Author: DaveDate: 22:35 05-08-08
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"John Popelish" <jpopelish@rica.net> wrote in message
news:w-udnSnEhasilwTVnZ2dnUVZ_sTinZ2d@comcast.com...
> Dave wrote:
>> Trying to use a (Motorola) MC14017 to drive a circuit to step through a
>> series of configurations, only I can't seem to be able to get it to
>> *count*. I have pin 16 connected to +5V, the clock running off of the Q
>> output of a 4027 J/K flip-flop, pin 13 (clock enable) hooked to +5V, and
>> pin 7 (decoded 3 output) set to hit pin 15 (reset) with a logic 1 when
>> the device counts that high. Only it doesn't count. If I unhook pin
>> 7/15 then pin 3 (decoded 0) goes high and stays there. Hook pin 7/15
>> back up, and the device seems to go dead. Pin 3 (decoded 0) never goes
>> high again. At my wit's end. Anyone have any idea what I might be doing
>> wrong? Have replaced the chip 3 times, with no differing result. Oh,
>> and pin 8 is grounded. Would love for someone to point out just how dumb
>> I am at this point...
>
> When the decode 3 output is connected to the reset, it stays high only as
> long as it takes for the reset to propagate through the chip. Are you
> able to see a fraction of a microsecond high on pin 7 with the equipment
> you are using?
>
> What do you connect to pin 15 when pin 7 is not connected to it?
>
> --
> Regards,
>
> John Popelish
Hey John,
Actually, I'm not trying to catch pin 7/15 going high, I'm trying to catch
the output of the appropriate pin on the 4049 being driven going high. And
the problem was my method of "enabling" the clock. Please see my reply to
BobW. Thanks though.
Take it easy...
Dave
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