UM11057
All information provided in this document is subject to legal disclaimers.
© NXP B.V. 2017. All rights reserved.
User Manual
Rev. 1.0 — 9 June 2017
11 of 14
NXP Semiconductors
UM11057
User Manual
6. Power
measurement
JP2 is provided to enable supply current to the LPC845 to be measured by placing an
ammeter in line with JP2 pins. By default this jumper is bypassed by solder jumper (SJ6).
Header P1 may be installed to measure supply power to the LPC845 by measuring
voltage drop across a 2.43 ohm resistor on the board.
7. Other board features
This section describes other board features not detailed elsewhere in this document.
7.1 ISP booting and the ISP button
The LPC845 can be forced into ISP boot mode by holding down the ISP button (SW1) and
then holding and releasing reset. The ISP button is connected via a 100 ohm resistor to
LPC845 pin PIO0_12, which is also routed to the LPCXpresso expansion connector (pin
45) and to the cathode of the red user LED. LPC845 pin PIO0_12 can be reconfigured by
software so that the button can be used by an application as a general purpose button
(refer to the LPC84x User Manual).
7.2 Wake button
The Wake button is for general purpose use by LPC845 applications. It is connected via a
100 ohm resistor to a 100K ohm pullup to 3.3V, and to the LPC845 PIO0_4 pin. This pin
can wake the LPC845 from deep power-down. Note that PIO0_4 is also connected to the
P3 LPCXpresso expansion connector (pin 50).
7.3 User LEDs
Three users LEDs are provided on the board, one blue, one green and one red. The
anodes of the LEDs are connected together, through solder jumper SJ1 to the 3.3V
regulator output. SJ1 can be opened to prevent leakage from the LPC845 pins through
the diodes if accurate power measurement measurements are being performed. The
LEDs are connected to the LPC845 as shown in
Table 6
.
Table 6.
LED connections
LED
LPC845 pin
Notes
Blue (D2)
PIO1_15
Shared with LPCXpresso connector pin 44
Red (D3)
PIO0_12
Shared with ISP pin and LPCXpresso connector pin 45
Green (D1)
PIO0_0
-