The PIC18C family can do CRC checksum.
I guess those UL guys need to invent more stuff to complicate things for
developers. They have to keep continuing their business. What's next? May=
be
a requirement that Microcontroller in a UL marked product must be UL labe=
led
to be used ;-)
Opps, maybe I should not joke about that, they might just pick that idea =
up
from this list.
To use WDT is also good too to prevent error. There is no such thing as a
totally fail safe system. The best you can do is put in more lifelines in
the system. If one doesn't work another one kicks in, and if all snaps th=
en
....booom.
Interesting to know that the UL guys is dictating what type of life line =
you
must use and not the end result.
In the beginning the UL guys only dictated that this and that cable or re=
lay
should endure this and that current without bursting to flame. More the e=
nd
requirement that is.
If a developer is inventing a new security lifeline that's better than
required from UL for his design. He or she  would probably not use it as =
it
would be additional cost in the design to have that at the same time as a
less good security required by UL.
Is that progress?
I vote for end result and not for limitations.
CRC is good but not the only thing for security.
I'm glad I do not work with UL products.
Niklas


-----Ursprungligt meddelande-----
Fr=E5n: pic microcontroller discussion list [mailto:PICLIST@MITVMA.MIT.ED=
U]
F=F6r Spehro Pefhany
Skickat:        den 6 mars 2002 15:32
Till:   PICLIST@MITVMA.MIT.EDU
=C4mne: Re: [PIC]: UL 1998 requirements

At 08:06 AM 3/6/02 -0600, you wrote:
>Has anybody dealt with UL 1998 requirements?  In some situations, this r=
ule
>requires a microcontroller to do a checksum on it's own memory.  If I
>understand this correctly, only the PIC 16F8XX flash parts are able to
>accomplish this.

Hi, Lawrence:-

There is also one non-FLASH member of the 16Cxxx family that can do it,
presumably Microchip developed it to meet the standards for safety-critic=
al
software such as UL1998. Sorry, I don't remember the exact part number at
the moment. I'd think that in your business an approved thermal cutoff
would be a better solution than trying to make a UL1998 limit controller.

Best regards,

Spehro Pefhany --"it's the network..."            "The Journey is the
reward"
speff@interlog.com             Info for manufacturers: http://www.trexon.=
com
Embedded software/hardware/analog  Info for designers:  http://www.speff.=
com
9/11 United we Stand

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body

--
http://www.piclist.com#nomail Going offline? Don't AutoReply us!
email listserv@mitvma.mit.edu with SET PICList DIGEST in the body