User manual

Low-power Application Kit (Oryx) - User’s Guide
Page 9
Copyright 2012 © Embedded Artists AB
3 The Low-power Application Board Design
This chapter describes the hardware design of the board.
3.1 Block Diagram
The block diagram in Figure 1 below gives a quick overview of a design. It illustrates the major
components in the design. The center of the design is the LPC11U37 MCU from NXP. A number of
low-power peripherals are connected to the LPC11U37 via the I2C and SPI interfaces. There is also a
USB Device interface to the LPC11U37 and all pins are available on an LPCXpresso/mbed compatible
expansion connector.
The board is powered from a rechargeable Lithium coin cell (LiR2032). The battery can be charged
from several different sources; the USB interfaces (when connected to a PC) and the expansion
connector. There is also an option to charge the battery from an external source, for example a solar
panel (not included). The board runs on 3.0V and there are possibilities to measure the current
consumption of the complete board and the LPC11U37 separately.
All parts of the design are constantly powered, with the exception of three parts. The constantly
powered parts can be put to low-power mode so that the idle current consumption is very low. Power
switches have been added on three of the external peripherals in order to allow control the power
consumption - (these parts has typically too high low-power consumption. These power switches exist
for the SPI flash, the memory LCD and the trimming potentiometer.
Figure 1 – The Low-power Application Board (Oryx) Block Diagram
LPC-LINK
Rechargeable
Lithium coin
battery
LPC11U37
LPCXpresso/
mbed compatible
expansion connector
USB
interface
USB
interface
SWD I/F
SWD I/F
3-axis accelerometer
I2C interface
RTC + Crystal
I2C interface
8 Capacitive sensors
I2C interface
Temperature sensor
I2C interface
External power
source (solar)
I2C
Trimming potentiometer
with power switch
4 Mbit SPI FLASH
with power switch
ISP enable
switch
96x96 memory LCD, SPI
interface with power switch
Power
Power
Power
LPCXpresso compatible
embedded SWD/JTAG
Wakeup
switch
AIN
SPI#0
USB
SPI#1
3.0V
Current
measurement