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10 KiB
10 KiB
------------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 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.