NAMC-EXT – Technical Reference Manual
Version 1.6
© N.A.T. GmbH
20
4.2.4
Wire Bridges
The wire bridges BR1 and BR2 connect the supply voltages. The supply current
can be measured between both contacts of one bridge if the respective wire
bridge is opened.
Please note:
Instead of using a simple ampere meter it is recommended to insert
a shunt resistor (e.g. 10 m
Ω
) between the contacts and measure the voltage drop
to calculate the current or to monitor it on an oscilloscope.
Both contacts of BR3 are connected to ground; it can be used as a reference
contact for measuring and/or to connect an external power supply (
NAMC-EXT-
PS
only).
Both contacts of BR4 are connected to +12V Payload Power; it can be used to
connect an external power supply to the extender board (
NAMC-EXT-PS
only).
The following table gives an overview of the wire bridges and the supplies they
connect.
Table 4:
Wire Bridges
Supply
Wire Bridge
+12V
Payload Power
BR1
+3.3V
Management Power
BR2
GND
(reference point or external supply)
BR3
+12V
Payload Power
(external supply)
BR4
4.3
Test points
There are a number of test points available on the
NAMC-EXT
. Due to layout reasons
there are only small SMD test points for the differential signals. All other signals (e.g.
geographical address, IPMB signals, etc.) are routed to standard test points, into which
standard 100 mil header connectors may be assembled. By default, there are no headers
assembled. The names of the signals carried by the test points are printed on the
silkscreen.
