DS1286 Help

Using Arduino General Electronics
1

OK so I pulled this Real Time Clock chip from an Indigo2 Motherboard (Something that greatly saddened me) and it seems like a very fancy one from what I read on the data sheet here: http://datasheets.maxim-ic.com/en/ds/DS1284-DS1286.pdf

The problem I am having is the way the pins are on the Package, first off it seems like a DIP embedded within a slightly larger plastic shell, fastened in there with epoxy of some kind, this is something I have not seen before, I have some really crappy pictures that probably wont help much but is all I have:

Top down view, the red numbers are the number of pins in the group highlighted

Horizontal view, showing the pins more clearly (relatively of course)

And finally a top down picture showing the numbers and dog face.

Any help would be appreciated.

2

It's a Dallas Semiconductor (now Maxim) clock chip with a built-in crystal and battery. As the doc says, it's a 28-pin EDIP (extra-wide). Pins 2 and 3 are internally connected to a crystal. It's designed for an 8-bit microprocessor bus so it has 8 data pins, 6 address pins, CE, OE, and WE. If the battery is still good (they last about 5 years) it should still be keeping time.

You can hook it to an Arduino using 17 data pins and try to read it.

3

Essentially, it's one of these: 146818 http://courses.engr.illinois.edu/ece391/references/mc146818.pdf

With a lithium battery backpack. Pins related to Standby, clock etc got "folded" up to the stuff added by Dallas.

They were designed to work with 8080, 8085, 8086, 6800, 6809, 68000, 6502 type processors.

4

I doubt the battery still works, or if so will work for much longer (its spec'd for 10 years +, but the module was made in 94 or 95 from what I can tell of the markings)

5

If the battery is dead you can try to resurrect the chip by cutting away enough of the plastic case to get to the battery pins and add a fresh battery on top. With I2C and OneWire clock chips available it's not a very useful part for an Arduino.

6

DS1286 good:

You've got one
It has an integral battery

DS1286 bad:

It has an integral battery. When that runs down, all your work to interface to yesterday's technology will no longer serve any purpose.

Alternative:

A modern Dallas RTC (real time clock) chip, with external battery. Not hard. Easy to replace battery. Longer time-to-no-longer-available.

Lots of choices.... one is...

.. the clock chip which is just one element in the nuElectronics shield.... which costs about $16.

Or Sparkfun's rtc only module...

$15, assembled. (As is the nuElectronics shield) The Sparkfun module comes with a replaceable battery, you'd have to add the battery backup to the shield.

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They both use Dallas RTCs... and the code for THOSE Dallas RTCs is already available on the 'net.

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