capt_key#
Overview#
This example shows how to use CAPT to detect key touch event. When the key is touched, LED on the board is on accordingly. The example first runs the calibration, in this period, all LEDs are on, please don’t touch any key at this time. After all LEDs off the example starts touch detection, touch any key and the LED turns on. This example only supports touch one key at the same time. CAPT sample data are saved in a window for later process. During calibration period, the variance of each channel is used to judge whether the channel is stable. Calibration finished only when all channels are stable. The stable value after calibration is saved as baseline, to be used in the detection stage. To remove touch glitch, a software filter is used in this example.
Supported Boards#
LPC845BREAKOUT
Hardware requirements
Micro USB cable
LPC845 Breakout board
Personal Computer
Board settings
Make sure R23 is on the LPC845 Breakout board.
Prepare the demo
Connect a micro USB cable between the PC host and the CMSIS DAP USB port on the board.
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
When touch the electrode plate, the corresponding LED would turn on.
LPCXpresso804
Toolchain supported
IAR embedded Workbench 8.22.1
Keil MDK 5.24a
MCUXpresso10.2.0
Hardware requirements
Micro USB cable
LPCXpresso804 board
CapTouch Shield board
Personal Computer
Board settings
Remove JP3, JP21, JP22, JP23, JP25 and C13 on LPCXpresso804 board.
Prepare the Demo
Connect a micro USB cable between the host PC and the LPC-Link USB port (J8) on the target board.
Open a serial terminal with the following settings:
9600 baud rate
8 data bits
No parity
One stop bit
No flow control
Download the program to the target board.
Either press the reset button on your board or launch the debugger in your IDE to begin running the demo.
Running the demo
When touch the electrode plate, the corresponding LED would turn on.