User`s guide

6
Host Computer Grounding
Case 1 - Desktop and Single-board Computers. The chassis on a
desktop or single-board host computer must be connected to
earth ground to comply with safety regulations. If the computer
chassis is NOT connected to earth ground for some reason (i.e.,
use of a two-prong power mains plug), the host computer power
supply ground will float to some unknown voltage potential.
Case 2 - Laptop Computers. Laptop computers present special
ESD problems. Most laptop computers use an external
double-insulated mains power supply which is NOT connected
to the mains earth ground. This means that the laptop chassis is
floating at some unknown voltage potential.
In either case, upon connection to the I
2
C Bus Monitor and the
target system, the host computer can discharge energy through
its interface card to the I
2
C adapter, and on to the target system.
This discharge could damage the host computer, I
2
C Bus
Monitor, and the target system.
Grounding Solutions
To avoid damage to the host computer, I
2
C Bus Monitor, or
target system, follow these instructions:
C Wear an earth grounded wrist strap, or discharge any static
charge build-up, when handling the I
2
C Bus Monitor or any
target system devices.
C Ensure that both the host computer and target system are
connected to a common earth ground point.