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XT-RTC - Level of interest

Found this on a Google: http://www.electronicsurplus.com/dallas-ds1216e-ic-smartwatch-rom-series-e

Price isn't bad and it come with the DIP socket. Just might jump on this one myself and squirrel it away for a while. BTW, I'm not sure where I bought the last one, but it may have been JAMECO.
Check the date code on that. Looks like it was made in the 25th week of 1989. So it's 25 years old. I know the battery in these things lasts a long time if it has not been activated, but still, 25 years is a long time.
 
Check the date code on that. Looks like it was made in the 25th week of 1989. So it's 25 years old. I know the battery in these things lasts a long time if it has not been activated, but still, 25 years is a long time.

Yep, that's a long time, I agree. But, it might be worth it just for the piggy-back DIP. You could always do a little surgery with a Dremel when the time comes. These things aren't going to be around for ever. BTW, the one I put in my 1000SX a year or so ago was from 1991 and its still got juice.
 
And there's always those clocks that sit under the CPU. No slot necessary there, either.

Not sure if it's of interest, but I do have one of these, pulled from a PC XT


Just wedges between the CPU, uses a simple coin battery, I was quite impressed by it.
 
Yep, that's a long time, I agree. But, it might be worth it just for the piggy-back DIP. You could always do a little surgery with a Dremel when the time comes. These things aren't going to be around for ever. BTW, the one I put in my 1000SX a year or so ago was from 1991 and its still got juice.

Is it possible that the unit as a whole could be new, but the 1216E was just made in 89, and sat around until someone slapped the unit together? It COULD be a new battery in there, with the old chip, assembled recently.
 
Is it possible that the unit as a whole could be new, but the 1216E was just made in 89, and sat around until someone slapped the unit together? It COULD be a new battery in there, with the old chip, assembled recently.

I think I'm going to roll the dice on that one and put it on ice (literally) until I need it for something.
 
Is it possible that the unit as a whole could be new, but the 1216E was just made in 89, and sat around until someone slapped the unit together? It COULD be a new battery in there, with the old chip, assembled recently.
I suppose it's possible but not likely in my opinion. I bought a new one from Maxim In January 2011 that had a date code 1007 meaning 7th week of 2010. Seems the date code on the chip was pretty close to the date of assembly of the rest of the device. Within a year anyway. That's not to say that they couldn't use old chips in recent production. I just don't think it's likely. To bad these are no longer in production. The original one that I bought in 1987 lasted 24 years!! Hoping the one bought in 2011 lasts that long.
 
You could even do SPI fully discrete with a three shift registers and combinatoral 74xx chips.
It's rather difficult to support all 4 SPI modes with simply "shiter" built from 74xxx chips. Looking into SPI6502B VHDL code, we need to remove dependence from the "phi2" 6502 bus signal and add a full ^IOW ^IOR decode a-la x86. Shifter and interrupt logic looks relevant.

http://6502.org/users/andre/spi65b/SPI6502B1.1.vhd
 
I really would like one.(or more) But please intergrate it on an 8 bit ISA I/O board.. So we dont have to waste one isa slot. And that would work with AT style RTC units for easier replacement.
I also can recommend a RTC chip that is highly available.. Otherwise replacement would be very hard in these days. (price of the RTC unit i dont care all) (vintage computers hobby do costs already a lot of money)
 
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