Your SlideShare is downloading. ×
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Capacitance Sensing - Waterproof Capacitance Sensing
Upcoming SlideShare
Loading in...5
×

Thanks for flagging this SlideShare!

Oops! An error has occurred.

×
Saving this for later? Get the SlideShare app to save on your phone or tablet. Read anywhere, anytime – even offline.
Text the download link to your phone
Standard text messaging rates apply

Capacitance Sensing - Waterproof Capacitance Sensing

3,199

Published on

Capacitance sensing systems can be used in applications that are exposed to rain or water. Such applications include automotive applications, outdoor equipment, ATMs, public access systems, portable …

Capacitance sensing systems can be used in applications that are exposed to rain or water. Such applications include automotive applications, outdoor equipment, ATMs, public access systems, portable devices such as cell phones, PDAs, and kitchen and bathroom applications. This Application Note discusses using capacitance sensing on systems that must continue operating under moisture, rain or water drops. The proposed technique prevents false touch detection even when the sense area is covered completely with water.

Published in: Technology
1 Comment
0 Likes
Statistics
Notes
  • This is an interesting article, if you are looking for detail information you can check out http://www.cypress.com/
       Reply 
    Are you sure you want to  Yes  No
    Your message goes here
  • Be the first to like this

No Downloads
Views
Total Views
3,199
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
0
Comments
1
Likes
0
Embeds 0
No embeds

Report content
Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
No notes for slide

Transcript

  1. Capacitance Sensing - Waterproof Capacitance Sensing AN2398 Author: Victor Kremin and Ruslan Bachunskiy Associated Project: Yes Associated Part Family: CY8C21x34, CY8C24x94 GET FREE SAMPLES HERE Software Version: PSoC Designer™ v. 4.3 Associated Application Notes: AN2352 PSoC Application Notes Index Application Note Abstract Capacitance sensing systems can be used in applications that are exposed to rain or water. Such applications include automotive applications, outdoor equipment, ATMs, public access systems, portable devices such as cell phones, PDAs, and kitchen and bathroom applications. This Application Note discusses using capacitance sensing on systems that must continue operating under moisture, rain or water drops. The proposed technique prevents false touch detection even when the sense area is covered completely with water. Introduction Table 1. Keyboard Characteristics The capacitance sensing technique can be effectively used in applications where the touch sensing zone is exposed to Characteristic Value moisture, rain, or water drops. PSoC® CapSense allows Number of Keys 3 you to replace expensive mechanical switches, improve device reliability, and reduce total system cost. Size of Sensors 15 × 15 mm 2 There are numerous areas where waterproof capacitance Host Communications Interface I C (for debug purposes) sensing can be used. In vehicle applications, examples Insulation Overlay Thickness 1-5 mm (glass or plastic) include door opening devices, code entry systems, alarm Power Supply Voltage 5 ± 0.25V sensors, and capacitive parking proximity sensors. Waterproof capacitive sensors can be used in a wide variety of home applications including kitchen equipment, bathroom Experimental Arrangement light switches, automatic faucets, and dish and clothes A simple test setup was created to test water’s influence on washing machines. Water resistant capacitive touch screens capacitive sensing. The CYC821x34 PSoC family device can be used on ATMs, PDAs, cell phones, portable GPS was used for testing with the CSD (CapSense Sigma Delta) navigation systems, and other devices that are used User Module sensing method. The PSoC device was placed outdoors. on the sensing board. To display sensor status, several The project created to test the water resistant capacitive additional LEDs were located on a small supplemental sensing technique under simulated application uses three board and connected to the PSoC board. This board can be simple buttons on a keyboard. You can expand the project placed at different locations during tests to aid sensors’ to fit your specific application requirements. For example, status observations. you can increase the number of buttons, use different button To monitor the sensor, raw counts, and other data during dimensions and shape, and so on. The technical realtime tests, an I2C-USB bridge was used. The bridge GUI characteristics of the associated project are shown in PC tool monitors multiple traces at the same time, logs them Table 1. to a file, and calculates scale and offset factors on the collected data. For more details about using the I2C-USB bridge to debug CapSense applications, see AN2352, quot;I2C- USB Bridge Usage.quot; Figure 1 shows the experimental environment. December 8, 2006 Document No. 001-14501 Rev. *A 1 [+] Feedback
  2. AN2398 Figure 1. Experimental Environment The sensor board contains three touch sensors, a guard sensor located around the perimeter and two shield Sensor Board electrodes connected in parallel. The three touch sensors are surrounded by the internal ring of the shield electrode. The internal shield electrode protects the button sensors from detecting false touches caused by water drops. The guard sensor is located between the internal and external rings of the shield electrode and is LED Display Board used to detect the presence of a water stream. The external shield electrode ring protects the guard sensor from PSoC Board detecting false touches caused by water drops. The shielding electrode also reduces the influence of parasitic capacitance by lowering the sigma delta modulator input current. See the CSD User Module Data Sheet in PSoC I2C-USB Designer for more details about shield electrode operation. Bridge Water is applied to the sensor board from the insulation layer side. To prevent the sensing electrodes from coming PC into direct contact with water, they are coated with an insulating varnish. The connection wires have waterproof insulation as well. The metal zone of the sensor board is The sensors are located on a separate plate and are 95*45 mm. Each sensor is a 15 mm square. The guard connected to the PSoC CapSense board using thin pliable sensor is 2.5 mm wide. wires. The sensors are located separately from the CapSense PCB so that the sensor board can be easily Test Setup Schematic subjected to different conditions, for example, applying a stream of water to the sensor board. Figure 3 shows the test setup schematic. The LEDs with current limiting resistors are installed on a separate display The sensor board was created using a 2-mm thick single board. The standard CY3212 or CY3213 board can be used side foil FR4 material. An illustration of the sensor board is for experiments. The CY3213 board supports the CSD shown in Figure 2. method. The CY3212 can be modified to support the CSD Figure 2. Sensors Board Drawing method by installing a modulator feedback resistor. 2,52 December 8, 2006 Document No. 001-14501 Rev. *A 2 [+] Feedback
  3. AN2398 Figure 3. Test Setup Schematic R4 240 CMOD 5V C4 10nF R6 2.2k 32 31 30 29 28 27 26 25 Vdd Vss P0[3] P0[5] P0[7] P0[6] P0[4] P0[2] R1 240 R3 240 1 24 P0[1] P0[0] 2 23 P2[7] P2[6] 3 22 P2[5] P2[4] R2 240 4 U1 21 P2[3] P2[2] 5 CY 8C21434 20 P2[1] P2[0] D1 D2 6 19 D3 D4 P3[3] P3[2] 7 18 Sens2 Guard Sens1 Sens3 P3[1] P3[0] 8 17 P1[7] XRES P1[5] P1[3] P1[1] P1[0] P1[2] P1[4] P1[6] Vss 9 10 11 12 13 14 15 16 FB J1 5V 5V 1 2 3 I2CSDA 4 I2CSCL 5 + C3 C2 100nF 10uF IS S P /I2 C SENS3 SENS1 SENS2 SHIELD GUARD Sens1 Sens2 Sens3 Figure 4. I2C-USB GUI Variables Setting Example Water Influence Tests The following was used for all testing of the influence of water on the raw sensor counts. The sensor board was set vertically during all experiments. Photos of the tests are shown in Appendix A. Tap water was used to test the board. To simulate worst-case conditions, some kitchen salt was dissolved in the water, resulting in increased water conductivity. Additionally, the effect of setting different modulator The following tests were completed: reference values during the water droplets test was examined. These results are discussed ahead. Touching the dry sensor with a finger. The first test checks the keyboard operation when no Applying water droplets from a sprayer when the water is present on the board and a finger touches all of shield electrode was connected to ground. the sensors sequentially (as shown in Figure 5a). As you can see in the figure, the finger touches are easily Touching the sensor with a finger after a water stream detectable. was applied and water droplets were left on the The second test checks the sensor functions when water insulator. drops are present on the sensor, the shield electrode is enabled, and a finger touches all of the sensors Applying water droplets from a sprayer when the sequentially (as shown in Figure 5b). As can be seen from shield electrode was active. the figure, small signal spikes take place because the finger first touches the water droplet, then the board. Applying a continuous water stream to the board from These spikes are negligible in comparison to the signal a large cup. from the finger and do not create any problems with touch The results of these tests are shown in Figure 5. To make detection. The finger touch signals are easily detectable. the collected data easy to visually analyze, the raw count data from different sensors were biased using the Offset feature in the I2C-USB bridge GUI PC tool. The settings from the example are shown in Figure 4. December 8, 2006 Document No. 001-14501 Rev. *A 3 [+] Feedback
  4. AN2398 Figure 5. Water Influence Test Results Dry Sensors Finger Touch with no Water Water Droplets with Shield Electrode Enabled 2 400 1 800 Sensor 1 Sensor 1 2 300 Sensor 2 Sensor 2 1 700 2 200 Sensor 3 Sensor 3 1 600 2 100 Guard Guard 2 000 1 500 1 900 1 400 1 800 1 300 1 700 1 600 1 200 Raw Counts Raw Counts 1 500 1 100 1 400 1 300 1 000 1 200 900 1 100 800 1 000 900 700 800 600 700 500 600 500 400 400 300 300 200 200 100 100 350 400 450 500 550 600 650 700 750 800 850 900 0 20 40 60 80 100 120 140 160 180 200 220 240 260 Sample # Sample # a) d) Wet Sensors Finger Touch Response after Water Stream Applying to Sensors Panel, sample #1 Applying Water Stream 2 400 2 400 Sensor 1 Sensor 1 2 300 2 300 Sensor 2 Sensor 2 2 200 2 200 Sensor 3 Sensor 3 2 100 2 100 Guard Guard 2 000 2 000 1 900 1 900 1 800 1 800 1 700 1 700 1 600 1 600 1 500 1 500 Raw Counts Raw Counts 1 400 1 400 1 300 1 300 1 200 1 200 1 100 1 100 1 000 1 000 900 900 800 800 700 700 600 600 500 500 400 400 300 300 200 200 100 100 200 250 300 350 400 450 500 550 600 650 700 750 1 000 1 100 1 200 1 300 1 400 1 500 Sample # Sample # b) e) Water Stream Applying to Sensors Panel, sample #2 Water Droplets with Shield Electrode Disabled 2 400 3 100 Sensor 1 2 300 Sensor 1 3 050 Sensor 2 2 200 Sensor 2 Sensor 3 Sensor 3 2 100 3 000 Guard 2 000 2 950 1 900 2 900 1 800 2 850 1 700 Raw Counts Raw Counts 1 600 2 800 1 500 2 750 1 400 2 700 1 300 2 650 1 200 1 100 2 600 1 000 2 550 900 2 500 800 700 2 450 600 2 400 500 2 350 400 2 300 300 200 2 250 100 400 450 500 550 600 650 700 750 800 850 900 950 500 600 700 800 900 1 000 Sample # Sample # c) f) December 8, 2006 Document No. 001-14501 Rev. *A 4 [+] Feedback
  5. AN2398 The third test checks the sensor functions when water is When a finger touches the dry surface, the finger adds sprayed on the board and the shield electrode is disabled capacitance Cx to the sensing electrode (Figure 6a). When (as shown in Figure 5c). As you can see in the figure, the an isolated water drop is located between the sensing and water spray can produce signal spikes close to the signal shield electrodes (Figure 6b), the capacitive coupling from the finger; the finger touch signal is 400 counts above between the shield and sensing electrodes is increased baseline, while the water drop signal is 200 counts, about (via Cwd and Cws capacitances). half. It may cause false touch detection under some When a continuous water stream is applied to the sensing conditions. surface (Figure 6c), the large capacitance of the stream The fourth test checks the sensor functions when water is Cst is added. This capacitance may be several times larger sprayed on the board and the shield electrode is enabled than the shield electrode-to-water capacitance, Cwd. (Figure 5d). As can be seen from this figure, the spike Because of this, the effect of the shield electrode is levels are more than six times less than the finger signal completely masked and the sensor raw counts are the and can be easily distinguished. Therefore, the shield same as or even higher than a finger touch. In this electrode effectively protects the keyboard controller from situation the guard sensor can help. When it detects the false touch detection. stream it can block the other sensors from triggering. The next test checks the sensor functions when a water Several additional tests were done using different sigma stream is applied to the board and the shield electrode is delta reference voltages to determine what effect they had enabled (Figure 5e, and Figure 5f). As you can see from on the tests. Two of these results are shown in Figure 7. the figures, the water stream produces signal spikes on all The area where there is little change in the raw counts is sensors with the same magnitude as a finger touch. These when the sensor is dry. Then water is sprayed on the will produce false touch detection. The guard sensor, insulator. however, produces signals with even higher levels than Figure 7. Raw Counts Change when Water Droplets were the touch sensors, because the guard sensor has a larger Applied at Different Reference Settings sense area. So the guard sensor can be used to detect the presence of a water stream on the board and 140 Ref=0.25Vdd implement blocking decision logic when a water stream is Ref=0.4Vdd 120 detected. 100 There are some illustrations to show CapSense 80 configurations during water tests. See Figure 6. 60 40 Figure 6. Sensing On Dry Surface (a), with Water Droplets 20 on Surface (b) and when Water Stream is Applied to 0 Surface (c) -20 -40 -60 -80 0 200 400 600 800 Sample # As you can see in Figure 7, at a low reference voltage the spikes are mostly positive, the same direction as finger touches. When the reference voltage is increased, peaks are mostly lower than the quot;no waterquot; level because when the water droplet is located between the shield and sensing electrodes, the modulator current is reduced more than with a higher reference. The spike direction is the opposite of a finger touch signal change. The high-level API routines can utilize this characteristic and yield benefits from this by not resetting baseline levels when there are short durations of negative spikes. This functionality is not supported in the current version of the CSD User Module v. 1.0 but may be added in future versions. December 8, 2006 Document No. 001-14501 Rev. *A 5 [+] Feedback
  6. AN2398 When water droplets are applied to the insulator, the water Demonstration Firmware can create thin films over the insulation surface, increasing The firmware uses the CSD User Module. Some post sensing electrode capacitance. This is why at low processing has been added to handle the guard sensor modulator reference voltages the raw count changes are signal. The updated baseline algorithm has been left more positive, while at higher voltages they are more without changes. The selected CSD User Module negative. This is due to the increased effect of the shield parameters are shown in Figure 9. Note that the Sensors electrode. Autoreset parameter has been enabled to allow baseline The objective is to get the maximum difference between updates regardless of sensor state. the finger touch signal and water droplet spike signals by Figure 9. CSD UM Parameters selecting the optimum reference voltage. This is especially true if the water droplets cause negative peaks because at this time, the CSD API resets the baseline to the minimum value. The Figure 8 shows water droplets quot;signal-to-noise ratioquot; for various reference voltages. Figure 8. Relation between Finger Touch Response and Water Droplets Noise for Different Reference Settings Water Droplet 6 “SNR” 5 4 3 2 1 The firmware scans the touch sensors and the guard sensor with different scanning parameters, FingerThreshold and Reference values, because touch 0 0,10 0,15 0,20 0,25 0,30 0,35 0,40 0,45 sensors and guard sensors have different areas used for Reference, x Vdd different purposes. The guard sensor is located around the touch sensors and the guard sensor area is distributed over a larger board area. The guard sensor should have As you can see from this figure, the maximum relation was better sensitivity and a lower FingerThreshold value than received at reference voltage 0.30 Vdd. That corresponds the touch sensor. to the Ref Value = 1 in the CSD UM parameters. This A special algorithm is used to provide reliable finger touch value will be different for different electrodes and overlay detection and eliminate false touch detection. This configurations, so your configurations may use different algorithm uses special resettable counters for each touch values. In another version of the sensor panel, the best sensor and the guard sensor, implemented in firmware. results were obtained at Ref Value = 2. These counters provide a debounce function. The touch The experimental results and simple model we used sensor counter sets the minimum time interval during clearly show that for reliable touch detection and which the sensor must be touched in order to be detected elimination of false detection caused by the water droplets by the decision logic. The touch counters allow you to and streams, a combination of shield electrodes and a eliminate short signal spikes caused by water leaks and guard sensor should be used. The shield electrode remove false touch detection. reduces the influence of water droplets at the physical The guard sensor counter allows you to eliminate false level and the guard sensor resets the decision logic touch detection due to the remains of the water on the operation at the logic level. The next section discusses the board after a stream of water is applied. When a water proposed high-level data processing scheme. stream is applied to the board, the guard sensor detects this event and disables the touch sensor processing logic. Additional guard sensor quot;deadquot; time prevents unlocking the sensor counters prematurely. When the water stream is gone, the guard counter suppresses touch processing for a short time. This eliminates false touch detection due to water remaining on the board. December 8, 2006 Document No. 001-14501 Rev. *A 6 [+] Feedback
  7. AN2398 The algorithm is shown in Figure 10 as a simplified equivalent electrical schematic so that its operation is easier to understand. Figure 10. Equivalent Simplified Schematic of the Post Processing Logic Counters Update Upon Scan Completion Guard Counter Sensors Array -1 Sg in Sg out Load En 0 Gcnt out S1 S1 in Multiple Touch Detection S2 S2 in S1 … Adder Sn >1 Sensor 1 Counter SN-1 SN-1 in +1 R1 S1 cnt out S1 out R =Thl En <Thl SN SN in Sensors Status Sensor N Counter SN cnt out SN out CSD API Post Processing Logic Counters are updated after the completion of each Reaching the counter maximum value signals sensor scanning cycle. The guard counter is loaded with its activation. Figure 11 shows the counter’s timing diagram. threshold value when the guard sensor is triggered. The counter is decremented until it reaches zero. The sensor counters are enabled when the guard counter reaches zero. When the sensor counter reaches the threshold value it stops incrementing the count and holds the maximum count value. December 8, 2006 Document No. 001-14501 Rev. *A 7 [+] Feedback
  8. AN2398 Figure 11. Timing Diagram of Guard and Sensor Counters Design Recommendations Guard Сounter Operational Diagram This Application Note can be used as a design foundation for other waterproof CapSense projects. From our SG out experimentation we developed several recommendations that you may find useful: • Place the sensors vertically or at an angle to the SGcnt out horizontal so that water drops naturally move off of the sensor plate and large water drops do not accumulate. tg del • Use a water-repellent, non-absorbent material as the front panel insulator. This minimizes water streaks and films on the device panel. This is especially Sensor Counter Operational Diagram important if the water is highly conductive. Seawater, for example. S1 out • The guard sensor is required in situations where the application may be subjected to continuous water ts del streams. It is not required if the device is subjected to S1 cnt out rain only. • The shield electrode between buttons should be at R least 10 mm wide. This allows you to effectively suppress the influence of water drops. Summary Sg out – The guard sensor detection signal. This Application Note demonstrates a waterproof capacitance sensing technique that can be used SGcntout – The guard counter output signal: ‘1’ when water successfully when the target detection area operates with is present, ‘0’ when water is not present. moisture, water films, drops, or even a continuous water tg_del – The minimum time interval after the last water stream. The device continues to function in the presence detection event before touch detection decision logic is of water drops and eliminates false triggering when a enabled. water stream is applied to the sensing zone. S1out – The first sensor touch detection signal. The post-processing algorithm can be used in other applications where reliable touch detection is required, for S1 cnt out – The first sensor counter output signal. example, in white goods where the system should not ts del – The minimum time interval during which sensor generate false triggers during cleaning. The software must be touched continuously in order to be detected as counter mechanism is effective for preventing touched by the decision logic. simultaneous touches of multiple sensors in conventional CapSense applications, for example, placing an arm or There is an additional mechanism in the API that tracks palm on the sensing zone. multiple sensor touches and resets all sensor counters when more than one sensor is touched at one time. It allows you to suppress false touch detection when a water stream is applied or the customer places their palm on the sensor zone. This mechanism is also useful when you have several sensors located horizontally and it is possible for a large water drop to cover several sensors at the same time. In this case, touching one sensor may trigger touch detection on all of the other sensors at the same time. The multiple touch detection mechanism prevents false detection in this situation. A full listing of the post processing logic is available in Appendix B. December 8, 2006 Document No. 001-14501 Rev. *A 8 [+] Feedback
  9. AN2398 Appendix A. Photos of Tests In Figure 12, photos of the different keyboard water tests are shown. Figure 12a) shows the dry keyboard test. A finger touch on the middle sensor turns on the middle LED. Figure 12b) shows water sprayed on the keyboard. As can be seen in the photo, no LEDs turn on. Figure 12c) shows a finger touching the middle sensor when water droplets are present on the board. The middle LED turns on. No false detection takes place. Figure 12d) shows a water stream applied to the keyboard and the guard sensor LED turns on. No other sensors can turn on while the guard sensor is active. Figure 12. Test Photos a) Dry Board Test b) Spraying Water on Board; c) Touching Sensor when Water Droplets are on Board; d) Applying a Stream of Water to Board a) b) c) d) December 8, 2006 Document No. 001-14501 Rev. *A 9 [+] Feedback
  10. AN2398 Appendix B. Post Processing Code //---------------------------------------------------------------------------- // C main line //---------------------------------------------------------------------------- #include <m8c.h> // part-specific constants and macros #include quot;PSoCAPI.hquot; // PSoC API definitions for all User Modules #define SENSOR_TOUCH_COUNT_TH 15 #define GUARD_TOUCH_COUNT_TH 10 #define GUARD_SENS_NUM 3 WORD iI2CBuf[CSD_TotalSensorCount]; BYTE touch_cnt_array[CSD_TotalSensorCount]; BYTE touch_cnt = 0; BYTE guard_state = 0; BYTE i; extern BYTE EzI2C_bRAM_RWcntr; void main() { M8C_EnableGInt; CSD_Start(); CSD_SetDefaultFingerThresholds(); CSD_baBtnFThreshold[GUARD_SENS_NUM] = 100; CSD_SetRefValue(0); CSD_InitializeBaselines(); for (i = 0; i < CSD_TotalSensorCount; i++) touch_cnt_array[i] = 0; EzI2C_SetRamBuffer(2*CSD_TotalSensorCount, 0, (BYTE *)iI2CBuf ); EzI2C_Start(); while (1) { CSD_SetRefValue(1); CSD_ScanSensor(GUARD_SENS_NUM); CSD_SetRefValue(1); CSD_ScanSensor(0); CSD_ScanSensor(1); CSD_ScanSensor(2); CSD_UpdateAllBaselines(); M8C_DisableGInt; if ((0 == EzI2C_bRAM_RWcntr) || (EzI2C_bRAM_RWcntr > (2*CSD_TotalSensorCount-1))) for (i = 0; i < CSD_TotalSensorCount; i++) iI2CBuf[i] = CSD_waSnsResult[i]; M8C_EnableGInt; touch_cnt = 0; for (i = 0; i < CSD_TotalSensorCount; i++) if (GUARD_SENS_NUM != i) { if (0 != CSD_bIsSensorActive(i)) { December 8, 2006 Document No. 001-14501 Rev. *A 10 [+] Feedback
  11. AN2398 touch_cnt++; if (touch_cnt_array[i] < SENSOR_TOUCH_COUNT_TH) touch_cnt_array[i]++; } else touch_cnt_array[i] = 0; } if(0 != CSD_bIsSensorActive(GUARD_SENS_NUM)) touch_cnt_array[GUARD_SENS_NUM] = GUARD_TOUCH_COUNT_TH; else { if (0 != touch_cnt_array[GUARD_SENS_NUM]) touch_cnt_array[GUARD_SENS_NUM]--; } guard_state = (touch_cnt_array[GUARD_SENS_NUM] > 0); if ((0 != guard_state) || (touch_cnt > 1)) for (i = 0; i < CSD_TotalSensorCount; i++) if (GUARD_SENS_NUM != i) touch_cnt_array[i] = 0; (0 != guard_state)?(PRT2DR |= 0x80):(PRT2DR &= ~0x80); (SENSOR_TOUCH_COUNT_TH == touch_cnt_array[0])?(PRT0DR |= 0x01):(PRT0DR &= ~0x01); (SENSOR_TOUCH_COUNT_TH == touch_cnt_array[1])?(PRT0DR |= 0x02):(PRT0DR &= ~0x02); (SENSOR_TOUCH_COUNT_TH == touch_cnt_array[2])?(PRT0DR |= 0x04):(PRT0DR &= ~0x04); } } In March of 2007, Cypress recataloged all of its Application Notes using a new documentation number and revision code. This new documentation number and revision code (001-xxxxx, beginning with rev. **), located in the footer of the document, will be used in all subsequent revisions. PSoC is a registered trademark of Cypress Semiconductor Corp. quot;Programmable System-on-Chip,quot; PSoC Designer, and PSoC Express are trademarks of Cypress Semiconductor Corp. All other trademarks or registered trademarks referenced herein are the property of their respective owners. Cypress Semiconductor 198 Champion Court San Jose, CA 95134-1709 Phone: 408-943-2600 Fax: 408-943-4730 http://www.cypress.com/ © Cypress Semiconductor Corporation, 2006-2007. The information contained herein is subject to change without notice. Cypress Semiconductor Corporation assumes no responsibility for the use of any circuitry other than circuitry embodied in a Cypress product. Nor does it convey or imply any license under patent or other rights. Cypress products are not warranted nor intended to be used for medical, life support, life saving, critical control or safety applications, unless pursuant to an express written agreement with Cypress. Furthermore, Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress products in life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. This Source Code (software and/or firmware) is owned by Cypress Semiconductor Corporation (Cypress) and is protected by and subject to worldwide patent protection (United States and foreign), United States copyright laws and international treaty provisions. Cypress hereby grants to licensee a personal, non-exclusive, non-transferable license to copy, use, modify, create derivative works of, and compile the Cypress Source Code and derivative works for the sole purpose of creating custom software and or firmware in support of licensee product to be used only in conjunction with a Cypress integrated circuit as specified in the applicable agreement. Any reproduction, modification, translation, compilation, or representation of this Source Code except as specified above is prohibited without the express written permission of Cypress. Disclaimer: CYPRESS MAKES NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARD TO THIS MATERIAL, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. Cypress reserves the right to make changes without further notice to the materials described herein. Cypress does not assume any liability arising out of the application or use of any product or circuit described herein. Cypress does not authorize its products for use as critical components in life-support systems where a malfunction or failure may reasonably be expected to result in significant injury to the user. The inclusion of Cypress’ product in a life-support systems application implies that the manufacturer assumes all risk of such use and in doing so indemnifies Cypress against all charges. Use may be limited by and subject to the applicable Cypress software license agreement. December 8, 2006 Document No. 001-14501 Rev. *A 11 [+] Feedback

×