NXP Semiconductors
UM10815
NXP Smartphone Quick-Jack Solution quick start guide
UM10815
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© NXP B.V. 2014. All rights reserved.
User manual
Rev. 1 — 19 May 2014
9 of 12
•
Press the phone’s Return button (Android) or the phone’s Home button (iOS) to exit
the app.
2.4 Jumper settings
Two jumper headers are available on the Quick-Jack board, jumpers JP2 and JP3
(Fig
8
):
•
JP2
(Power) -
Power supply select
. Four-pin header JP2 allows placing two
jumpers. The left (outer) jumper connects the energy-harvester to the input of the
LDO, the right (inner) jumper connects the coin cell battery to the input of the LDO.
Diodes prevent current flowing from one source into the other, allowing Quick-Jack to
be powered by both the battery and the energy-harvester at the same time. This
operation is advised when using Quick-Jack and is the default setting.
•
JP3
(Communication) –
Left-channel audio signal path select
. This jumper can be
positioned in either the left- or right position. When placed on the right two pins, the
phone’s left-channel audio signal – the signal with the Manchester encoded data – is
routed through the on-board comparator (default mode).
•
When placed on the left two pins, the on-board comparator is bypassed and the
analog signal is fed straight into the LPC812. In this case, the LPC812’s internal
comparator must be enabled and configured in order to convert the phone’s analog
data to digital data. Note that this mode is not supported in the default firmware.
Fig 8.
Jumper JP2 and JP3 and their default position
