Magtek MDYNAMO, Installation And Operation Manual

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2 - Electrical Integration
mDynamo| EMV Contact Reader / Transaction Hub Module | Installation and Operation Manual
Page 12 of 27 ( D998200144-14 )
2 Electrical Integration
2.1 Grounding / ESD Protection
Figure 2-1 – mDynamo Chassis Ground Points
Figure 2-1 shows red highlights on all points on mDynamo that share a common earth ground plane:

The four mounting screw pads

The housing of USB Port [J3]

Pin 10 of Auxiliary SPI Port [J7]

Pin 10 of Auxiliary UART Port [J8]
To guard against ground loops and to protect the chip card contact block against electrostatic discharge
(ESD), it is important to ground the device correctly. MagTek strongly recommends checking whether
the host provides earth ground on its USB port shield, and whether the selected USB cable carries that
ground all the way to the shield of
USB Port [J3] on the board. This will help make an informed
decision about proper grounding:

If the solution design, including the host, provides earth ground to the shield of USB Port [J3] , no
additional ground connections are necessary.

If the solution design does not provide earth ground to the shield of USB Port [J3] , the solution
design should connect one or more of the other points in Figure 2-1 to a common chassis ground.
Ideally the chosen ground would be earth ground, because only an earth ground connection provides
ESD protection.

After deciding which points will be grounded, make sure none of the remaining ground points in
Figure 2-1 are connected to a different ground. For example, carefully trace from Pin 10 of the
auxiliary ports through any connected devices to make sure they do not lead to different grounds.