Olin Lathrop wrote:
> Douglas Wood wrote:
>> I've not ever seen a micro with RS-anything built into the micro
>> itself. I wouldn't want one, either. If the RS-485 (or
>> RS-422/232/etc.) part of the circuit got fried, you'd have to replace
>> the entire micro, not just the much less expensive transceiver chip.
> 
> This seems to be a common position, but does it really matter?  In most
> cases if the unit fries, you are going to replace the whole unit.  Whether
> that's due to the RS-232 interface or the micro doesn't make any difference.
> It just doesn't make sense to spend $50 technician time to diagnose and
> repair the problem on a $40 board.

Olin, I've seen fried transceiver chips on tons of equipment. I've
referred to them as self sacrificing (I think others have too). It
got to the point that when a particular board came in to be repaired
that I'd just replace the Moto MC1489 without any other testing. 95%
of the time the board would work. The $2 (US) part would save a $1500
board (this was back in the mid 80's). I still kind of design things
that way today (sacrificing parts separate from the main board). Of
course I just do it as a hobby now which is definitely a different
prospective from the board swap culture today.

-- 
Linux Home Automation         Neil Cherry       ncherry@linuxha.com
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