2 - Electrical Integration
mDynamo| EMV Contact Reader / Transaction Hub Module | Installation and Operation Manual
Page 16 of 27 (
D998200144-14
)
2.7
External LED Connector [J2]
The External LED connector, labeled
J2
and
LED
on the printed circuit board, can be used to drive an
external LED. It is a 4-pin 1.25mm pitch Molex PicoBlade header designed to mate with Molex
PicoBlade connector
51021-0410
. The dot printed on the circuit board indicates pin 1. Pinouts of the
connector, and a reference design for the green portion of the LED connector, are shown in
Figure 2-5 – Pinouts and Green LED Reference Implementation for mDynamo LED Connector J2
The connector can drive either an encapsulated red/green three-pin LED with common cathode (allowing
for amber blending) or separate red and green LEDs. The connector provides 3.3V up to 24 mA. Each
LED should have a current-limiting resistor connected in series, with values calculated as
R=[(3.3V -
V
LED
) / I
LED
] Ohms
, where V
LED
is the characteristic voltage drop across the LED (typically 2V) and I
LED
is optimally between 10mA and 20mA. Solutions that incorporate amber should carefully select and test
current limiting LED resistor values that provide a proper mix that doesn’t look too green or too red.
By default, the device drives
J2
to match the General Status LED (see section
). However, custom software on the host the device is connected to may override the
External LED behavior.
