UG133 Datasheet, PDF (6/17 Pages) List of Unclassifed Manufacturers – CPT112S SLEXP8008A Kit

4. Power and Operation
UG133: CPT112S SLEXP8008A Kit User's Guide
Power and Operation
4.1 Power Selection
The CPT112S Capacitive Sense Evaluation Board is designed to be powered by two different sources:
• Through the on-board USB.
• Through the EXP header.
The figure shows how the different power sources are connected to the device.
USB Mini-B
Connector
Internal
ToolStick
LDO
Automatically
Switches
EXP
Header
CPT Device
and
Peripherals
Figure 4.1. CPT112S SLEXP8008A Power Supply
When the USB is connected, the board is powered from the LDO internal to the USB device, which is in turn powered by the USB
cable.
The board can also be powered externally through the VMCU and GND pins of the expansion header when the board is attached to a
power supply or an EFM MCU Starter Kit.
When power is provided through the USB or an external power supply, the device can act as a stand alone device. When it is connec-
ted to an EFM MCU Starter Kit through the expansion header, the device acts as a peripheral to the MCU by providing capacitive sense
capabilities.
4.2 Standalone
In standalone mode, the CPT112S SLEXP8008A on the CPT112S Capacitive Sense Evaluation Board is designed to showcase and
test the board's features or act as a breakout board for any application. To operate in this mode, apply power using the USB connector
or an external supply.
The board can operate on its own to demonstrate and test the board's touch features and functionalities. The CPT112S SLEXP8008A
features configurable options such as touch characteristics, output characteristics, and user feedback peripherals. The device's fea-
tures can be configured in Simplicity Studio using [Xpress Configurator], and the capacitive sense data can be viewed in the [Capaci-
tive Sense Profiler].
The device can act as a breakout board to extend functionality of a custom board by simply reading the output results on the pins. The
touch qualification engine on the device will process the touch information and output the results through I2C. The device outputs can
be accessed through the expansion header, and the capacitive sense inputs can be accessed through the vias on the board.
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