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clock chip with multiplexed BCD output ?

 
   All About Circuits - Newsgroup Archive Forum Index -> sci.electronics.components


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Gerry Jacobs
Guest





PostPosted: Wed Dec 10, 2003 3:51 pm    Post subject: clock chip with multiplexed BCD output ?

I am intending to build a Nixie clock with the SN74141 as driver for the
nixies. The 74141 takes BCD as input.

Is there any clock chip out there which provides BCD output and seperate
signal pins for each digit to multiplex the BCD output across the four
digits ?

All I could find are chips which drive LCDs directly. However output to
control the LCD/LED segments is not particulary useful since I need BCD
input.

I really would like to save the expense to use a microcontroller to do the
job.

TIA

Gerry
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Sal Brisindi
Guest





PostPosted: Thu Dec 11, 2003 7:08 am    Post subject: Re: clock chip with multiplexed BCD output ?

Gerry,
There were many clock ic's manufactured with BCD outputs but good luck trying
to find them. The numbers are MM5311, MM5312, MM5313 and I think MM5315. The
other one is FCM7002 (CT7002) with alarm and calander. There is a decoder chip
you can use that decodes 7 segment to BCD, that chip is the rare 74C915. but
you can find it for about $7.00 and use the MM5314 clock ic which is still
available. Hope this information helps.

Sal
www.tuberadios.com/nixie

Gerry Jacobs wrote:

Quote:
I am intending to build a Nixie clock with the SN74141 as driver for the
nixies. The 74141 takes BCD as input.

Is there any clock chip out there which provides BCD output and seperate
signal pins for each digit to multiplex the BCD output across the four
digits ?

All I could find are chips which drive LCDs directly. However output to
control the LCD/LED segments is not particulary useful since I need BCD
input.

I really would like to save the expense to use a microcontroller to do the
job.

TIA

Gerry
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Michael
Guest





PostPosted: Thu Dec 11, 2003 10:56 am    Post subject: Re: clock chip with multiplexed BCD output ?

Gerry Jacobs wrote:
Quote:

I am intending to build a Nixie clock with the SN74141 as driver for the
nixies. The 74141 takes BCD as input.

Is there any clock chip out there which provides BCD output and seperate
signal pins for each digit to multiplex the BCD output across the four
digits ?

All I could find are chips which drive LCDs directly. However output to
control the LCD/LED segments is not particulary useful since I need BCD
input.

I really would like to save the expense to use a microcontroller to do the
job.

TIA

Gerry



Expense? Implement both the clock and the BCD generator with just a
micro. Since I happen to be a PIC bigot I would use a $2.60 PIC16F628,
but an Atmel or Motorola or whatever would do just as well.
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Sal Brisindi
Guest





PostPosted: Fri Dec 12, 2003 5:49 pm    Post subject: Re: clock chip with multiplexed BCD output ?

Michael,
I would love to learn how to program am Pic or AVR so I can create my own clock
ic's. I have a bunch of the Atmel 2313'2 and a developement board, one day I
have to sit down, read a book and give it a shot.

Regards,
Sal

Michael wrote:

Quote:
Gerry Jacobs wrote:

I am intending to build a Nixie clock with the SN74141 as driver for the
nixies. The 74141 takes BCD as input.

Is there any clock chip out there which provides BCD output and seperate
signal pins for each digit to multiplex the BCD output across the four
digits ?

All I could find are chips which drive LCDs directly. However output to
control the LCD/LED segments is not particulary useful since I need BCD
input.

I really would like to save the expense to use a microcontroller to do the
job.

TIA

Gerry

Expense? Implement both the clock and the BCD generator with just a
micro. Since I happen to be a PIC bigot I would use a $2.60 PIC16F628,
but an Atmel or Motorola or whatever would do just as well.
Back to top
Michael
Guest





PostPosted: Sun Dec 14, 2003 10:05 pm    Post subject: Re: clock chip with multiplexed BCD output ?

Sal Brisindi wrote:
Quote:

Michael,
I would love to learn how to program am Pic or AVR so I can create my own clock
ic's. I have a bunch of the Atmel 2313'2 and a developement board, one day I
have to sit down, read a book and give it a shot.

Regards,
Sal


Sounds like you have what you need to get started. Go for it. I think
you won't regret it. uC's are great little tools; cheap, very capable,
very flexible. Though the learning curve might be steep - depends on
the learner's aptitude and capabilities - like anything else worth doing
it's worth the effort.

I'm an old guy (50+) who started out with tubes in the early 1960's,
moved to semiconductors in the late 60's, and to IC's (TTL) in 1969.
Six years later I started and then finished an EE degree, went to work
for a major large computer company for 15 years, and only after all of
that water was under the bridge did I get my feet wet in micros.
Started with the Z80 in 1994 when the Z80 was all but dead. Quickly
moved to PICs, the 16F84, then 16F84A, and finally the 16F628. I prefer
100% assembly language, never use a compiler or interpreter. Assembler
keeps the mind sharp, in my opinion. Wink
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