Single chip for digital clock.

[SylvainP]

Hello all, I'm new here and was not sure where to put my question. I'm a newbie here but started in electronic in the 1970's. But I'm relatively inexperienced because I left the hobby for computers in the 80's. I did not throw away my equipment and parts and continued adding to it from time to time because I did want to come back to it one day. That day came when I had to stop working for medical reasons.

This place needs a forum where new member can introduce themselves but maybe this is it? (or did I miss it?)

Anyway, my father recently told me that he can find a 24 hour alarm clock, i.e. one that display 14:00 instead of 2:00 with an AM/PM indicator. So thought to myself I could build him one for his birthday in December. I could do it easily enough with discrete logic chips or a microcontroller but it seems to me that someone must make a chip that does it all already. So, does such a beast exist?

Thanks in advance.

P.S. English is not my first language.

[carcanhol]

Hope this helps, i'm no pro either 
http://www.decodesystems.com/clock-ics.html
http://www.paulanders.com/G5-LED/ver1/datablad.pdf
http://www.electro-tech-online.com/articles/pic-single-chip-4-digit-24-hour-clock.678/

Also:Search for LM8560 in google then images.

[SylvainP]

Thanks carcanhol, the LM8560 seems like a winner.

[edavid]

If you don't want to build one, you can look for a ham shack clock:

http://www.eham.net/reviews/products/61

This one seems like a good choice:

http://www.mfjenterprises.com/Product.php?productid=MFJ-113

[SylvainP]

The LM8560 seems obsolete, I could only find it on ebay. I checked digikey, mouser, and a couple of local places and none have it. If the clock was for me I wouldn't mind but since it's not I want something I can easily fix if.

This one seems like a good choice:
http://www.mfjenterprises.com/Product.php?productid=MFJ-113

Bookmarked just in case thanks.

I found this one listed SCL5458 by Allegro. It is an automotive 2 function clock for vacuum fluorescent displays.
Probably a challenge to find one but you never know what some old small shops may still have.
http://pdf.datasheetcatalog.com/datasheets/1150/502515_DS.pdf

Thank you.
I'm not sure yet if I'm going to go with LED or LCD but I'm not going for a fluorescent display for the same reasons I just gave at the top, I do not want to go with obsolete hard to get parts.

[SL4P]

Sorry about the schematic style - I just wanted to capture it at the time - very simple.
PIC 16F628  + Maxim DS-3231 + SURE Electronics DP-002 4x7 LED

This is as simple as it gets - with the benefit of LARGE DIGITS (for old guys like me) !
Cost is minimal - running on perfboard from a DC plugpack. (was cheaper 5 years ago!)
n.b. 7805 regulator is not shown
Holds time really well (DS3231) plus a Supercap to carry across blackouts.
Decent LED segments that don't dim/or fail like retail chinese crocks.

The PICC-C code is ugly, but it has been working for a few years now - I just wanted a clock that I didn't have to re-set or replace every 2-3 years !
An alarm could be added, but I didn't need one at the time - a good starter project for some.
Display is 24-hours, but could easily be re-coded for 12/24hr operation.

http://store.sure-electronics.com/led/led-display/de-dp23711
Source for IM if you're interested.

[edavid]

The LM8560 seems obsolete, I could only find it on ebay. I checked digikey, mouser, and a couple of local places and none have it. If the clock was for me I wouldn't mind but since it's not I want something I can easily fix if.

The problem with that is that *all* dedicated alarm clock chips are obsolete (except maybe China-only parts that you won't be able to get).

[picandmix]

There is not that much difference between a micro and a ready made clock chip, which as you are finding there are not many around these days as its so easy to incorporate a rtc into most micros.

This link has a very easy to build micro led clock and he has a few others clock projects with extra functions or big displays; think it would be a much more interesting project for you.

http://bogdi.ro/electronics/digital%20clock/

[bills]

I got one of these for my grandkids to build works well.
http://www.ebay.com/itm/DIY-LED-C51-4-Bits-Digital-Electronic-Clock-Suite-Production-Kits-Parts-/141682975468?hash=item20fcf6a2ec

correction it was this one.
http://www.ebay.com/itm/DIY-AT89C2051-6bits-Digital-LED-Electronic-Clock-Digital-Clock-Kit-/181525540222?hash=item2a43c3ed7e

[SylvainP]

Sorry about the schematic style - I just wanted to capture it at the time - very simple.
PIC 16F628  + Maxim DS-3231 + SURE Electronics DP-002 4x7 LED

This is as simple as it gets - with the benefit of LARGE DIGITS (for old guys like me) !
Cost is minimal - running on perfboard from a DC plugpack. (was cheaper 5 years ago!)
n.b. 7805 regulator is not shown
Holds time really well (DS3231) plus a Supercap to carry across blackouts.
Decent LED segments that don't dim/or fail like retail chinese crocks.

The PICC-C code is ugly, but it has been working for a few years now - I just wanted a clock that I didn't have to re-set or replace every 2-3 years !
An alarm could be added, but I didn't need one at the time - a good starter project for some.
Display is 24-hours, but could easily be re-coded for 12/24hr operation.

Thank you, I have decided to go the micro-controller way after all. I do want to design my own clock but that does not mean I can't take inspiration from what other people have done. 

The LM8560 seems obsolete, I could only find it on ebay. I checked digikey, mouser, and a couple of local places and none have it. If the clock was for me I wouldn't mind but since it's not I want something I can easily fix if.

The problem with that is that *all* dedicated alarm clock chips are obsolete (except maybe China-only parts that you won't be able to get).

You seem to be right, micro-controller it is then.

There is not that much difference between a micro and a ready made clock chip, which as you are finding there are not many around these days as its so easy to incorporate a rtc into most micros.

This link has a very easy to build micro led clock and he has a few others clock projects with extra functions or big displays; think it would be a much more interesting project for you.

http://bogdi.ro/electronics/digital%20clock/

Thanks for the link, I want to design my own but other clocks schematics are a good source of idea for what parts to use, specially for the display and the 1 Hz source.

I got one of these for my grandkids to build works well.
http://www.ebay.com/itm/DIY-LED-C51-4-Bits-Digital-Electronic-Clock-Suite-Production-Kits-Parts-/141682975468?hash=item20fcf6a2ec

correction it was this one.
http://www.ebay.com/itm/DIY-AT89C2051-6bits-Digital-LED-Electronic-Clock-Digital-Clock-Kit-/181525540222?hash=item2a43c3ed7e

Wow, this is really cheap. If I did not want to design my own then I'd surely pick this one. If my god-son was still a kid then that would have made a great gift. Heck I might end up getting it just for the parts.

[picandmix]

You need to address the hardest part of the design first  - is it going to be mains or battery powered and then finding a neat case for it all the fit into.