UM11158
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© NXP B.V. 2019. All rights reserved.
User manual
Rev. 1.2 — 25 April 2019
20 of 24
NXP Semiconductors
UM11158
LPCXpresso55S69 Development Board
SDIO port 1 of the LPC55S69 is routed to the expansion connector to provide access to
this interface. Note that the power enable signal used for this SDIO interface is not one of
the port pins that supports in SD1_POWER_EN function; this because all port pins that
support this function are required for other features of the board. PIO1_16 is used instead
for the power enable function, configured as a GPIO.
9. Board Power
This section describes miscellaneous board features that we not covered elsewhere in
this manual.
9.1 LPC55S69 ADC references and inputs
By default, the LPC55S69 ADC positive reference is connected to VDDA and the negative
reference to ground. Different reference voltages may be used by moving the zero ohm
link J8 or J9 (for positive or negative reference respectively) from the 1-2 to the 2-3
position, and connecting an external reference to P15 (pin 1 for positive, pin 3 for
negative).
An external differential ADC input signal can be applied at P28 or at the P19 expansion
connector. This connection is routed to PIO0_16 and PIO0_23.