EA-APP-002 Embedded Artists, EA-APP-002 Datasheet - Page 15

• Manufacturer Part Number: EA-APP-002
• Description: Development Boards & Kits - ARM LOW POWER APP KIT LPC11U37 (ORYX)
• Manufacturer: Embedded Artists

Specifications of EA-APP-002

• Rohs: yes
• Product: Demonstration Kits
• Tool Is For Evaluation Of: LPC11U37
• Core: ARM Cortex M0
• Interface Type: I2C, USB
• Operating Supply Voltage: 5 V

Copyright 2012 © Embedded Artists AB
Low-power Application Kit (Oryx) - User’s Guide
R30 can be replaced with R29 via SJ1 (connect pad 2-3 instead of pad 1-2, which is default) if the
default value of 30 ohm is not suitable. Be careful to select a proper value for R29 so that the 50 mA
maximum shunt current of LTC4071 is not exceeded. See LTC4071 datasheet for details.
A low dropout linear voltage regulator is use to convert the battery voltage to 3.0V. TPS78330 from
Texas Instruments is used for this. It is a 3.0V/150mA LDO in SOT23-5 package.
JP3 is normally shorted with a jumper but if removed the current consumption of the board can be
measured over R34 (5 ohm resistor). 10mA current will give a 50mV voltage drop over the 5 ohm
resistor.
R33 can also be used for measuring the current consumption. It is by default a zero ohm resistor but
an arbitrary value can be used to measure current in the best resolution for a specific application. The
series resistor value is always a trade-off between voltage drop and noise/resolution in measurement.
3.4.6
J7 is an expansion connector that is compatible with the LPCXpresso and mbed products, both signal-
wise and physically. J7 has the same signal connections as the LPCXpresso LPC11U37 board.
3.4.7
This part of the design is the embedded SWD/JTAG part, called LPC-LINK. The design is based
around the LPC3154 MCU. The LPC-LINK is identical with the LPCXpresso boards and the
LPCXpresso IDE can be used to download and debug applications on the LPC11U37 MCU.
LPC-LINK is not an open design and there is no possibility to download custom code in the LPC3154.
J1 (LPC11U37 SWD interface) and J10 (LPC-LINK SWD/JTAG interface) shall be connected via a 10
pos flat cable (25 mil pitch). The flat cable is included.
If another debug interface than the LPCXpresso IDE is needed, for example from IAR, Keil or Rowley,
there is a possibility to connect J1 to any other SWD compatible debug interface. Note that not all, and
in particular older, JTAG debug probes do not support the SWD interface standard. The flat cable
between J1 and J10 is then simply removed. This will disconnect the on-board LPC-LINK completely
and it will not affect the current consumption of the board when inactive.
3.5
3.5.1
When measuring the trimming potentiometer, the voltage (to the trimming pot.) must be present for
about 50us before a reliable measurement can be done. The reason for this is because C11 and the
trimming potentiometer form a low-pass filter.
3.5.2
If the Lithium battery is removed and then reinserted into the board, and there is no other power
source, then the Lithium battery will be disconnected from the board. This is how the Lithium battery
charger (LTC4071) is supposed to work. A short voltage pulse on the input to the Lithium charger is
needed to connect the battery again. This is simply done by inserting a USB cable (connected to a PC)
on the LPC-LINK side. Make sure that jumper JP2, pos 1-2 is inserted.
Alternatively, SW4 is pressed. That will also connect the Lithium battery as a power source.
Things to Note about the Hardware
Page 7
Page 8-10
Trimming Potentiometer
Lithium Battery
Page 15