Real Time Clock RTC on JR-IDE Rev A (Texelec)

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JrCharles
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Real Time Clock RTC on JR-IDE Rev A (Texelec)

Post by JrCharles »

Some Texelec JR-IDE's Made in spring 2020 have the battery holder soldered in upside down. To fix you can do the soldering yourself or Texelec will graciously send you new clock chips. This pic shows the correct orientation. Note Battery hold down location
jrIDE-Side-3a.jpg
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chuckphd53
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Re: Real Time Clock RTC on JR-IDE Rev A (Texele

Post by chuckphd53 »

Charles…

Have you had the issue of using RTC.COM and it giving error when trying to set DOS time rtc /d ???
Different versions of the RTC.com were suspect to run or not !

with my Rev 'C' board all versions work fine !!!
This has prompted me to write this topic up....

I have tried to contact kevin, but have not talked to him yet…

I had a similar issue with my rev ‘C’ board, and reading the RTC chip with RTC>COM,
in that I left off the 32khz crystal and when I built the board in my haste and then tried to read the clock chip...
I got an ERROR because the time/date format was ‘junk’….
After I installed the crystal it worked fine ….(of course)

Alan's Rev'B' also does not suffer from this due to the fact that on his board the crystal is right next to the chip leads
this is the correct placement !

But started to think, Kevin has put this crystal on the TOP of the chip on a carrier board.
I have done many designed with clock chips in my embedded designs for customer over the years and this is a well known problem with clock crystals.
This crystal needs to be as close to the chip as possible...

The fact that it is on a carrier above the chip, MAY, not necessarily have ill effects on the freq. being further away...
These lower Freq crystals are sensitive to capacitance and 'moisture' More below on this....

If someone want's to experiment, if I talk to kevin he would be the best to do this, but others can also if they are interested..

NOTE: ONLY the chip should be in the socket, without the battery carrier that REV 'A' has...
With the Rev 'A' board, on pins 2 and 3 ( the crystal pins X1 , X2) tack solder the crystal right to these pins and it can hang off for testing keeping the leads as short as possible.
Now test the RTC.COM /D to ensure you can read from the clock chip to update DOS...
if you had a version of the RTC.com that did not work, try it to see it if does in fact now work....

The Crystal....
I heard a few folks talks about the TIME does not keep properly !..
Ok, to fix this, go borrow your wife or girlfriends clear enamel nail polish and coat the crystal and carefully coat the chip pins as well.
this will keep room humidity from affecting the capacitance and varying the freq. as it has a tendency to do in open air...
Folks that live up north, have more moisture in the fall and winter and this can make this issue of clock drift more noticeable...

Now for the folks that have REV'A' board with the piggy back battery and crystal, you can also coat the crystal and all open connections
down to the chips pins 2 and 3 same as above to keep moisture from affecting the freq.
I am not sure if this will help the issue of RTC.COM not working but I suspect it may help...
so you can test this easily...

run the RTC.COM that fails, confirm it is 'broken' with that version of RTC.COM you are running.
enamel over the crystal and leads let it dry for afew minutes, ultraviolet light will cure it in a few seconds..
and then run the same RTC.COM to see if it still fails or hopefully now runs fine...

Report your results...if you play with this and let us know...

In any case, anyone that has an JRIDE should locate the clock crystal and coat it with some enamel, conformal coat, or nail polish clear.
you can also coat the side of the chip pins to keep them from the outside air...
this will help the timekeeper freq of the crystal from drifting...
“I never commit to memory anything that can easily be looked up in a book.” (AE)

JrCharles
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Re: Real Time Clock RTC on JR-IDE Rev A (Texelec)

Post by JrCharles »

So, one of my Rev A board's RTC is showing older dates. Maybe the date when I previously shut down the Jr. I will try my other Board to see if the same problem occurs.

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