Re: How to Un-Hang a DS RTC Chip Stuck in I2C La-La-Land ???

B1ackwater wrote:
I've been working with a Real-Time-Clock chip, the DS-1337+, and
noticed that if the final I2C read operation isn't accompanied
by a 'no-ack' then I2C communications hang-up shortly thereafter.
The PIC language I'm using (MikroPascal) does not have a proper
"time-out" for I2C operations, so everything hangs until the
watchdog finally kicks in, which is rather inelegant.

The docs say the 'no-ack' condition is necessary - but communications
are known to fail once in a great while (so I've heard) and that means
that one out of 'X' READ commands will be malinterpreted.

What the data*** does NOT say is what one can DO about this
situation - beyond cycling power on the RTC chip to reset
everything.

No biggie for something sitting on your desk ... but my app is
going to way out 'yonder "in the field" and needs a way to cope
with any I2C hang-ups on its own.

Is there a decent way to UN-hang a Dallas RTC chip, one that
doesn't destroy the time/date/alarm registers ?

Any info helpful.


If your code cannot terminate the read by a non-ACK,
it is violating the base I2C specification - no can do.

--

Tauno Voipio
tauno voipio (at) iki fi

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