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Thanks Thomas,
Clearly anytime any part of the chip might be operating outside of specs
enhances the odds for something going amiss. I had not known that bit of
history on EEPROMs. Just started using embedded chips about 4 years ago -
still lots to learn.
Ed
Ed Anderson
Rv-6A N494BW Rotary Powered
Matthews, NC
eanderson@carolina.rr.com
http://www.andersonee.com
http://www.dmack.net/mazda/index.html
http://www.flyrotary.com/
http://members.cox.net/rogersda/rotary/configs.htm#N494BW
http://www.rotaryaviation.com/Rotorhead%20Truth.htm
-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of thomas walter
Sent: Thursday, July 02, 2009 10:26 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: frustrating couple of days
Ed,
Odd electrical trivia. Older eeproms were rated at 3.3V, so below 2.7V
they ignored any read or write information.
We had a uC that would start "jabbering" on the data and clock lines when
power was caming up. Since reset occurred once power was good, it was
never an issue. Problem is the eeprom manufactures started shipping parts
that were functional from 1.8V to 3.3V. So once power was at 1.7V, it
accepted writes, corrupting the eeprom. Just to drive the engineers crazy
only some lots and some devices 'jibbered' away. Yes, amazing I still have
any hair left. :)
That is pretty rare, but has happened.
Yes, Mike -- Interesting you're only seeing an issue with the "B"
controller. Still triple check the power, grounds, and rest of the
connections.
> Since the fuel map is stored in non-volute memory, it’s hard to figure out
how it is being re-written or destroyed. Normally (as you know) access to
EEPROM on a chip is a rather non-trivial process. Since the A and B
controller are two different chips, I suppose there could be a problem with
the B chip – but, while that does happen, it’s pretty rare. Have not had
one myself (yet).
--
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