BMD-34x-EVAL User Guide
Rev 2.0
13
6.7
NFC Connector
Connection to an external NFC antenna is provided through a Molex flat-flex connector, Part
number 051281-0594.
Capacitors ‘C2’ and ‘C3’ provide tuning of the NFC antenna for resonance at
15.56MHz.
Figure 10
–
NFC Connector
6.8
Current Sensing Headers
The evaluation board provides two current sensing headers.
‘JBMD’ allows for power consumption
measurement of the BMD-34x
Module and ‘JSHD’ allows for power consumption measurement of
shields connected to the Arduino-
style headers (‘VSHLD’ power only).
Each 3-
pin 0.1” pitch header has two pins connected across a 1Ω current
-sense resistor powering the
module or the shield, and the third pin to ground. To measure current consumption, use a multimeter
or other precision voltage measurement device to measure voltage drop across pins one and two.
Current can al
so be measured directly by removing ‘RBMD’ / ‘RSHD’ and using a current meter in
series with the two voltage pins. The default hardware configuration does not require any
modification of the current sense headers for the BMD-3xx-EVAL to perform properly.
Note
: Only current flowing through ‘VBMD’ into the module is measured; current sunk through GPIO
pins is not measured.
Figure 11
–
Current Sensing Header Layout
