7 May
2012
7 May
'12
12:07 p.m.
On May 7, 2012, at 14:49, "Chuck Guzis" <cclist at sydex.com> wrote:
On 7 May 2012 at 13:36, Doc Shipley wrote:
In the TI app note I mentioned, it often comes down to the ESD protection diodes. If the
data pins are energized before Vcc or ground, you can get some pretty significant current
through those diodes.
This isn't the app note I was looking for (I have it filed away somewhere, maybe at
work), but it does cover the basics:
http://ics.nxp.com/support/documents/logic/pdf/hot.swap.pdf
- Dave
I've never personally blown a PS/2 port,
but I have worked on
computers with blown ports, and invariably the user/owner was prone to
swapping keyboards with the machine running. I don't kow if that's an
odds thing or cumulative damage, but in my experience the PS/2 port is
just not hot-pluggable in the long run.
I think that's mostly a design issue. In the MCU projects I've
worked on using a PS/2 keyboard for input, I've never had an issue
with hot-plugging. Quite often, I'll plug in a keyboard after the
MCU program has started. Since outputs are all supposed to be open-
collector, I don't see how damage could occur, unless it's from
something like ESD.