Datasheet
NXP Semiconductors
UM11121
LPCXpresso51U68
UM11121
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© NXP Semiconductors N.V. 2018. All rights reserved.
User manual
Rev 1.1 — 27 April 27, 2018
17 of 22
Table 4. Expansion connectors
Reference
Description
J1
The odd number pins are compatible with Arduino Uno rev3 Digital
15:8, AREF, SDA & SCL connector. The even numbered pins are
used for external access and expansion of LPC51U68 signals not
used by the Arduino Uno rev3 compatible interface.
J2
The odd numbered pins 1 – 13 are compatible with Arduino Uno rev3
Digital 7:0 connector. The even numbered pins, and odd numbered
pins 17 and 19, are used for external access and expansion of
LPC51U68 signals not used by the Arduino Uno rev3 compatible
interface.
J3
PMod™ connector. Connected to the LPC51U68 Target MCU
Flexcomm 3 port (for SPI or I2C use). This port is shared with the
Link2 debug probe for SPI to USB bridging; install JP3 when using
the PMod connector in order to disable the Link2 connection.
J7
The even numbered pins 6 – 20 are compatible with Arduino Uno
rev3 Power connector. The odd numbered pins, and even numbered
pins 2 and 4 are used.
J8
The even numbered pins 2 – 12 are compatible with Arduino Uno
rev3 Analog connector. The odd numbered pins are used for
external access and expansion of LPC51U68 signals not used by the
Arduino Uno rev3 compatible interface.
9. Buttons
The LPCXpresso51U68 board has 4 push buttons available to control the operation of
the LPC51U68 (target) MCU. Their functions are as described below.
9.1 Reset
This button is used to reset the LPC51U68 (note that the Link2 is NOT reset by this
button.)
9.2 ISP0 and ISP1
These button connect to the LPC51U68 P0_31 (ISP0 button) and P0_4 (ISP1 button) pin
and may be used to force the LPC51U68 into its various ISP boot modes. See Table 5.
Table 5. ISP boot mode control
Boot mode
ISP0
ISP1
Vbus (from J5)
I2C/SPI boot
Pressed
Pressed
X
UART boot
Pressed
Not pressed
0
USB Mass storage
Pressed
Not pressed
1
Boot from internal flash
Not pressed
Not pressed
X