MSP430-Capacitive-Touch-BoosterPack.zip_Capacitive touch _MSP430

------------MSP430G2-LaunchPad CapTouch BoosterPack User Experience------------- Ver.: 1.00 Initial Release February 2011 Dung Dang MSP430 Applications Texas Instruments, Inc. -------------------------------------------------------------------------------- CONTENTS I. DESCRIPTION II. PROJECT & FILE CONFIGURATION III. PROJECT IMPORT IN CCS & IAR IV. CAP TOUCH LIBRARY V. TOUCH & GESTURE DEFINITIONS VI. UART COMMUNICATION PROTOCOL VII. HISTORY I. DESCRIPTION ----------------------------------- This application operates on the LaunchPad platform using the MSP430G2452 device and the CapTouch BoosterPack plugin board. The capacitive touch and proximity sensing are enabled by the pin oscillator feature new to the MSP430G2xx2 family devices. The User Experience application also utilizes the cap touch library to realize & measure the capacitive touch and proximity sensors. The cap touch library also provides layers of abstractions to generate higher logical outputs such as logical touches, geometry (in this hardware, a four-button wheel), and even gestures. The User Experience application starts up and remains in 'sleep' mode, sampling the proximity sensor every ~8.3ms [VLO/100=12kHz/100=120Hz]. Upon registering a valid proximity event [hand/finger/object hovering ~3-5cm from the BoosterPack], the application wakes up to operate in the 'active' mode. During the wake up period, the LEDs surrounding the wheel light in a wake-up sequence, starting with a slow clockwise and ending with a fast counter-clockwise motion. As this sequence ends, the device enters active mode. In active mode, the application samples and registers individual finger touches on the 16-position wheel or the center button as well as simple gestures [Clockwise & Counter-clockwise] while the finger moves along and remains on the wheel. Upon wheel position detection, the corresponding LEDs surrounding the wheel light up accordingly. Each individual tap on the center capactive touch button toggles the center LED. After a predetermined amount of time without any touch activity (on the wheel or on the center button) the application returns to sleep mode, enabling only the proximity sensor periodically. A 9600 baud UART link is also implemented using SW TimerA to provide application and cap touch data to the PC via the UART-USB back channel. The application sends UART data upon events such as wake up, sleep, touch, or gesture. II. PROJECT & FILE CONFIGURATION ----------------------------------- PROJECT ROOT - CapTouchBoosterPack_UserExperience | CapTouchBoosterPack_UserExperience.c | <Main application code> | README <This file> | uart.c <C file: UART implementation using TimerA & SW> | uart.h <H file: UART implementation using TimerA & SW> | +---[CapTouchLibrary] <Capacitive Touch Library Code> | Cap_Touch_HAL.c | Cap_Touch_HAL.h | Cap_Touch_Layer.c | Cap_Touch_Layer.h | requirements.doc | structure.c <Created using template_structure.*> | structure.h <Configured/calibrated specifically for this HW> | +---[CCS] <CCS Project Configuration Files> | | <All listed files are required> | | <The non-listed can be safely removed> | | .ccsproject | | .cdtbuild | | .cdtproject | | .project <Contains links to portable project folders/files> | | lnk_msp430g2452.cmd | | macros.ini <Enables portable project> | | MSP430G2452.ccxml | | | \---All other folders & files: IDE/build generated files remove/ignore when exporting projects | \---[IAR] <CCS Project Configuration Files> | <All listed files are required> | <The non-listed can be safely removed> | CapTouch_BoosterPack_UserExperience.ewd | CapTouch_BoosterPack_UserExperience.ewp | CapTouch_BoosterPack_UserExperience.eww \---All other folders & files: IDE/build generated files remove/ignore when exporting projects Legend: [Directory] |---filename III. PROJECT IMPORT IN CCS & IAR ----------------------------------- 1. Project Import in CCS a. Open CCS. b. Select a new project workspace outside of the project folder* c. Select Project-->Import Existing Project d. Browse to the [PROJECT_ROOT]\CCS folder e. Select Finish *Ideally, workspace should be in completely independent folder, not containing or contained by the project/package folder. !Note: For CCS, while project root is in the outer directory, the CCS project files are located inside CCS. To enable the portability of the project, the file macros.ini is created to define the root. Additionally, all project code files (*.c, *.h) are added as linked resources with their relative path to the project root. 2. Open project & workspace in IAR a. Browse to the [PROJECT_ROOT]\IAR folder b. Open the CapTouch_BoosterPack_UserExperience.eww workspace. IV. CAP TOUCH LIBRARY The MSP430G2-LaunchPad CapTouch BoosterPack User Experience uses the Cap Touch Library to configure, calibrate, and control the capacitive sensors. The sensor pads are configured in the structure.h & structure.c files. Specifically 6 elements are divided into three sensors: 1 proximity sensor, 1 cap touch button (center button), and a 4-element wheel. After each element is calibrated to determine the touch threshold as well as their maximum values in number of counts (which correlate to the measured capacitances), these calibration values are also registered inside structure.c. The cap_touch_hal.* files provide the hardware abstract layer for the cap touch library, which essentially provides different hardware/peripheral options to drive the cap touch functionality. Specifically for the CapTouch BoosterPack using an MSP430G2xx2/MSP430G2xx3 device, the Pin Oscillator peripheral is used. The cap_touch_layer.* files provides the cap touch layer, which offers functions that process the raw data into structured format. The main application utilizes this layer for their API calls to setup, measure baseline, detect touches, and detect wheel positions. For more information on the Cap Touch Library, refer to the Cap Touch Library documentation. V. TOUCH & GESTURE DEFINITIONS ----------------------------------- Proximity Sensor The proximity sensor is made of the entire top PCB layer surface that covers the capacitive touch wheel. The proximity sensor detection occurs when the measured capacitance increases due to the presence of some conductive object within 1-2 inch from the surface. Generally, a hand wave motion in parallel and 1-2 inch from the CapTouch BoosterPack can trigger the detection. Individual Cap Touch Presses The center button (small round button in the middle of the board) can register an individual touch/press. The capactive touch wheel consists of four physical "ninja-star" elements arranged in a wheel formation that is calibrated & programed to provide 16-position detection. These positions can be detected individually as a button press. A press by the application's definition is consituted by a separate and single position detection registered continously [i.e. press begins when the position is touched and after no other position was detected, and ends when another position is detected or no further position is dectected. Wheel