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- ------------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.
-
- 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 Gesture
-
- A gesture on the capacitive touch wheel is formed when a continuous series of
- touches is detected (no no-detection is reported, i.e. finger never leaves the
- wheel). A complete continuous finger motion on the wheel might consist of
- several intermediate gestures, each with one separate direction (clockwise or
- counter-clockwise).
-
- VI. UART COMMUNICATION PROTOCOL
- -----------------------------------
-
- Per each event (wake up, go to sleep, touch/press, or gesture), a UART packet
- of two bytes is sent. They are specified as follows.
-
- WAKE UP [due to proximity sensor detection]: 0xBE 0xEF
- SLEEP [after period of inactivity]: 0xDE 0xAD
- CENTER BUTTON PRESS: 0x80 0x80
- WHEEL POSITION TOUCH/PRESS [z = touch position]: 0x3z 0x3z [z=1 nibble 0x0-F]
- GESTURE START [z = touch position]: 0xFC 0x2z [z=1 nibble 0x0-F]
- GESTURE STOP: 0xFB 0xFB
- GESTURE & GESTURE END POSITION : 0xGG 0x2z
- GG = [binary] b????????
- First bit is direction: 0 = clockwise, 1 = counter-clockwise
- Last 7 bits = count of gesture movement
- z = ending position of the immediate gesture [[z=1 nibble 0x0-F]
-
- The UART receiver can decipher the packets by comparing them against the fixed
- values (WAKE UP, SLEEP, CENTER BUTTON PRESS, GESTURE START & STOP) or against
- ranges (WHEEL TOUCH = 0x30-0x3F, GESTURE = 0x00-0x1F, GESTURE POSITION =
- 0x20-0x2F)
-
- VII. HISTORY
- -----------------------------------
-
- Ver. 1.0
- - Implemented 64-position detection in the cap touch layer (defined in
- structure.h/c fies). These 64 position are still translated into 16-position
- representational wheel.
- - Instead of sending continuous wheel touch packets, only send initial, last
- and every other WHEEL_TOUCH_DELAY wheel touch detections. This modification does
- not affect the MSP430G2-LaunchPad CapTouch BoosterPack User Experience GUI, but
- enables full and expected behavior of the MediaPad program in Windows.
- Ver. 0.9:
- -Initial firmware release for small lot production. Supports MSP430G2-LaunchPad
- CapTouch BoosterPack User Experience GUI. Partial support for MediaPad,
- application behavior might not be optimized.
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