Renesas Capacitive Touch Lab R8C/36T-A Family Description: This lab will cover the Renesas Touch Solution for embedded capacitive touch systems. This lab will demonstrate how to setup and run a simple touch project, and cover simple tuning of the touch system using the Renesas workbench tool. Lab Objectives Build a simple touch project and execute on demo platform Use Renesas Workbench to test and tune the touch platform Skill Level Use Renesas Workbench to test and tune the touch platform Build a simple touch project and execute on demo platform Lab Materials Please verify you have the following materials at your lab station. Laptop PC with Renesas tools preinstalled o Workbench 4.60 or greater o HEW o FDT 4.08 RSK36T-A Touch Demo Platform o Demo Board o E1 o USB Cable This lab sheet Time to Complete Lab 60 Minutes Lab Sections 1 Renesas Kit First Touch... 2 2 Introduction to Renesas Workbench... 3 3 Running the Renesas Demo with the E1 Debugger... 6 4 API Examination... 8 5 Programming the Target with FDT... 9 6 Selecting Touch Parameters... 13 Capacitive Touch Lab Page 1 of 14
1 Renesas Kit First Touch Overview: This lab section will get the board plugged into the laptop and give the user a 1 st exposure to the Renesas Capacitive Touch Evaluation System. A brief description of the board operation is discussed below: Number Keys (0-9, # and, *): Touching any of the keypad keys will display that key on the LED display. Touching additional numbers will place that number into the display in the rightmost position and shift the remaining numbers leftward. Slider: Sliding a finger up and down the slider area will increment the count on the display positively and negatively according to the direction of movement Wheel: Moving a finger around the wheel will increment or decrement the display count positively and negatively according to the direction of movement Mode: Pressing the MODE button will enable the onboard light sensor and display the current Analogto-Digital (ADC) converter reading on the display To return to normal operation, press the mode button again When enabled, an LED will light above the MODE button to indicate that the mode is active Enter: Pressing the ENTER key will enable the on-board buzzer that is activated when any key in the number pad is pressed. The buzzer will not sound when the wheel or slider is activated To disable the buzzer, press the ENTER button When enabled, an LED will light above the ENTER button to indicate that the buzzer is active Perform the following steps to power-up the board and start the lab exercise. Step 1.1 Turn the board over and ensure that the jumpers on the board are set as follows: J5: 2-3 position JP2: 2-3 position Step 1.2 Step 1.3 Plug the USB cable into connector J33 on the demo board Plug the other end of the USB cable into a USB port on the lab laptop Once powered, the board LED display will show 0000 and the ON/STBY LED will be illuminated. Step 1.4 Take a few moments and interact with the kit, examining the functions as outlined above in the kit operation description Capacitive Touch Lab Page 2 of 14
2 Introduction to Renesas Workbench Capacitive Touch Lab Overview: Renesas provides a free tool that allows users easy evaluation, testing, and tuning of touch parameters. This tool, knows as Workbench, has the following features that allows the user access to numerous parameters of the touch solution: graphically shows touch events in real time on the target system, allows for uploading and downloading parameters related to touch, contains a touch teaching tool that allows users to train the touch system and software circuit calibration wizard that allows the user to predict touch charge circuit values based in input hardware parameters The Workbench tool can connect to the hardware platform thru a number of different interfaces. These are: Serial (UART, SPI, I2C) USB (USB-to-serial converter) E1 via HEW Target Server Procedure: Step 2.1 Step 2.2 Step 2.3 Step 2.4 Leaving the kit plugged-in from the previous section, start the Workbench tool by using the Windows Start Menu, Start->All Programs->Workbench4->Workbench. The Workbench tool will open in its default, unconnected state Connect to the running HEW target system with Workbench by using the menu bar Communication->Connect. A dialog box will with auto filled connection parameters. CLICK OK. Once connected open the Setup Parameters table by clicking on the menu bar Touch senor- >Setup Parameters. The table will auto-fill with all the current parameters of the board and touch operations Now let s startup the status monitor and take a look at how the touch looks from a graphical point of view. Perform the following steps: Step 2.5 Step 2.6 Step 2.7 Step 2.8 Open the Status Monitor window by clicking on the menu bar Touch senor->status Monitor In the status monitor window click the Start button. You will see the values begin to stream in and the current count values of each channel in the display window Click the ALL button to center each of the graphs in each of the display windows. Touch the #1 button on the board. You should see a RED bar display once you touch the panel and go away once you remove your finger from the panel. It will look similar to the picture below. Capacitive Touch Lab Page 3 of 14
Step 2.9 Use the tabs above the data windows and select TAB 6. Channels 24-27 should appear on the screen Step 2.10 On the left-side of the screen, click on CH26 and change the selection on CH23 Step 2.11 Now, slowly move your finger around the wheel diagram on the demo board. You should see waveforms on channels 23-27 change in a similar pattern as shown in the below picture. Note your values for the indicated channels will be different than what is shown in the picture. This basis of touch gives the user a starting point to realize wheel, and other advanced button operations. Now let s move to a simple tuning example. Step 2.12 On the Workbench tab, switch back to the Setup Parameters tab. Capacitive Touch Lab Page 4 of 14
Step 2.13 Ensure that the 0 tab is selected so that channels 0-7 are shown Step 2.14 Change the Judging change (THRx) on CH0 from its current value to 400 Step 2.15 Write back the values to the device memory using the Write->To Device button Step 2.16 Click OK to when the dialog box completes the download process to the device. Step 2.17 Using the tabs switch the display back to the Status Monitor display within Workbench Step 2.18 Click the Start button to begin the graphical display. You will see that the CTHR value is updated and the touch graph for that channel displays a large step change indicating that you have changed the threshold for that channel. Step 2.19 Touch the #0 button. You will see that while the waveform indicated a touch, the touch is not registered because you have now changed the threshold used to detect a touch. Step 2.20 Return to the status monitor screen and set the threshold back to its original value by repeating steps 2.12. to 2.17 above Drift Compensation Demo The Renesas Touch API also features drift compensation that will allow for environmental or other concerns that might arise during the operation of the end application. The API will constantly track the current count value of each channel and modify the reference value (Cref) as needed. However if a touch is taking place, drift compensation is disabled so that any compensation to the reference is not skewed by the tough event. Note it does not modify the threshold value for the channel as that is independent of and tracks with the reference value. Step 2.21 Take the included penny with your lab and place it on the power button on the demo board. You may see a short touch event register on the workbench which will stop once you are not touching the conductive penny anymore. Capacitive Touch Lab Page 5 of 14
Step 2.22 You should see a similar waveform as to above. First the current touch count value (RED line) will drop with the addition of the penny onto the touch surface. Shortly thereafter the Cref line (BLUE line) and the Cthr line (GREEN line) will drop to reflect the new count value being detected on that channel. Step 2.23 Touch the penny at this point. The kit will still register a touch even though the values have all been adjusted by the API s drift compensation. Step 2.24 Remove the penny. This will return the channel value to it s original position after a short period of time. 3 Running the Renesas Demo with the E1 Debugger Overview: This lab section will expose the user to the Renesas Touch API using a simple sample project running under HEW and using the E1 debugger interface. Procedure: Step 3.1 Step 3.2 Step 3.3 Close the Workbench application by clicking on Communication->Exit Disconnect the USB cable from the demo board Connect the E1 debugger to JP1 on the board with the alignment tab facing up as shown in the below picture. The tab will be on the same side as the overlay panel Capacitive Touch Lab Page 6 of 14
Step 3.4 Step 3.5 Step 3.6 Step 3.7 Connect the USB cable as described before into the target board Start the High-performance Embedded Workspace by clicking on Start->All Programs- >Renesas->High Performance Embedded Workshop-> High Performance Embedded Workshop to start the IDE Load the following project into HEW by clicking the Browse radio button and navigating to the following directory to load the file: C:\Workspace\YR8C36TKIT02\Renesas_Touch\Renesas_Touch.hws NOTE: You may encounter a Warning at this stage of Workspace movement. If this occurs, simply click YES and the project will load normally. The project should load into HEW and the project files can be browsed in the workspace Step 3.8 Start the debugger session by using the pull down on the Menu Bar and select SessionR8C_e1_E20_System NOTE: You may get a message that the project has been modified. Click Yes to continue Step 3.9 In the Emulator Mode dialog box, ensure the following: R8C/36T-A Group is selected R5F213xCS Debugging Mode NOTE: A window will appear that will ask the user to select the Power Supply to the target being programmed. Since the USB cable is used, do not select this option Step 3.10 Click Next and Finish at the following screens. The debugger will now connect to the target Step 3.11 Once the debugger connects and the workspace opens, right click the Renesas_touch.abs file in the workspace pane. It can be found in the Download Modules folder in the Workspace pane. Select Download and the module will download to the target. The below picture shows that operation NOTE: The target is now programmed and is ready to run. We can now move to running the target and seeing touch events using Workbench. Capacitive Touch Lab Page 7 of 14
4 API Examination Capacitive Touch Lab Overview: This section will provide a brief overview of the Renesas Touch API and the major functions needed to add touch to an embedded design. The kit demo code provides an example of how the API is embedded into the end application A short definition of the major files you will see within the example project are as follows: touch_control.c - configures the T-SCU peripheral and allows modifying the configuration of the SCU. The DTC is also configured as part of this module since the DTC is required for proper SCU operation. Touch_interrupt.c controls interrupt functionality once a touch scan is completed Touch_user_API.c high level application interface file where a user application can control all functions of the API Wheel/slider_control.c integrated wheel and slider functionality built-in the Renesas Touch API Procedural Steps Step 4.1 Step 4.2 Step 4.3 Add a Watch Window to the project by clicking on the HEW menu bar View->Symbol->Watch A watch window will appear In the watch window, add variables by a right-click in the watch window and selecting Add Watch from the menu box that appears In the dialog box, enter the following variables exactly as typed: BDATA wheel_sw sldposition_r NOTE: You will have to repeat the right-click process for each variable to add them to the watch window. Step 4.4 Single left-click each variable to highlight it. Step 4.5 Click the black R at the top of the watch window or click the button to enable run-time refresh of that variable during program operation. Do this for each of the variables. At completion your watch window should look similar to shown below Capacitive Touch Lab Page 8 of 14
Step 4.6 Step 4.7 Step 4.8 Now in the watch window, click on the plus sign to expand the BDATA variable. Once expanded you will see an array that will represent the current count value for each of the touch channels available on the R8C/36T-A For element [0] of BDATA, change the display radix of the variable by right-clicking on the WORD, selecting Radix and selecting Binary as the display mode Also in the watch window, change the display radix of the wheel_sw and sldposition_r to DECIMAL as the display mode following the same procedure as above. The watch window should look similar to below once the operations are complete Step 4.9 On the HEW tool bar, click the farthest left icon in the debug set of buttons. Alternatively this can be performed by using the menu bar by clicking Debug->Reset CPU Step 4.10 Run the target by clicking the GO button in the tool bar or by using the menu bar and clicking Debug->Go. The stop sign should turn RED and the yellow PC bar will disappear. Once running, the watch window can be viewed to see the individual button presses along with the raw values of the wheel and slider processing NOTE NEED TO OPEN A SEPARATE PROJECT HERE FOR THE FOLLOWING SECTION. DON T USE THE E1 FOR CHANGING PARAMETERS 5 Programming the Target with FDT Overview: For the next lab section, we ll use Flash Development Toolkit (FDT), a Renesas flash programming interface, to program the board with a new, un-tuned, touch application program. This short section simply covers programming the board and quickly introduces the FDT Basic interface. Procedure: Capacitive Touch Lab Page 9 of 14
Step 5.1 Close the previous HEW session by clicking File->Exit. Answer YES at all the menus and windows to close the application NOTE: DO NOT REMOVE THE E1 at this time Step 5.2 Step 5.3 Step 5.4 Step 5.5 Step 5.6 Step 5.7 Step 5.8 Step 5.9 Start the programming application with: Start->All Programs->Renesas->Flash Development Toolkit 4.08->Flash Development Toolkit 4.08 Basic The application will then startup on the laptop screen Click on Options->New Settings In the Filter window, type R5F2136CS Click NEXT to move to the next window Select E1 in the pull-down menu for Select Port Click NEXT to move to the next window Click NEXT to move to the next window Click FINISH to complete the setting window Step 5.10 Click on the ARROW button to open the File Selection menu and select BROWSE Capacitive Touch Lab Page 10 of 14
Step 5.11 Returning to the PC application, click OPTIONS in the application toolbar. Once the menu opens, click on Erase Device Before Program and ensure it is checked if it is not Step 5.12 Click OPTIONS in the application toolbar. Once the menu opens, click on Readback Verify and ensure it is checked if it is not Step 5.13 Click OPTIONS in the application toolbar. Once the menu opens, click on AutoDisconnect and ensure it is checked if it is not Step 5.14 Click on the ARROW button to open the File Selection menu and select BROWSE Step 5.15 Navigate to the directory C:\Workspace\YR8C36TKIT01\Lab_2\Debug Step 5.16 Single click the Renesas_Touch_2.mot file and select OPEN The file will now load into the programming application Capacitive Touch Lab Page 11 of 14
Step 5.17 Moving to the touch board, move JP2 to the 1-2 position Step 5.18 Ensure J5 is in the 2-3 position Step 5.19 Program the device by clicking the PROGRAM FLASH button in the middle of the PC application Step 5.20 Programming a device the 1 st time will require that the E1 remember the power that the target requires and other internal information. A screen will appear stating that the E1 needs to download new firmware. This process will happen automatically and no user intervention will be needed. NOTE: This screen might not appear Step 5.21 A window will appear that will ask the user to select the Power Supply to the target being programmed. Select power via E1 and use the 5.0V selection here Step 5.22 A Select USB Device dialog box may appear. Click OK at this box Step 5.23 The programming operation will only take a few seconds. Once complete, you will see in the bottom of the application window this information: Capacitive Touch Lab Page 12 of 14
Step 5.24 Once complete, the device is now programmed for the next lab section Step 5.25 Exit the FDT application by clicking File->Exit Step 5.26 Unplug the USB cable, then the E1 connector from the board Step 5.27 Re-insert the USB cable Capacitive Touch Lab 6 Selecting Touch Parameters Overview: Tuning capacitive touch designs can be challenging at times, especially as the channel count in any particular design. This final lab section will outline a straightforward procedure that can be used to tune the touch channels quickly. Procedure: Step 6.1 Step 6.2 With the board plugged into the USB port, start the Workbench application as previously done in this lab exercise In Workbench, start the Status Monitor as performed previously in the lab exercise NOTE: for this lab section, we will only use channels 0-4 (buttons 1-5) on the demo board for brevity Step 6.3 Step 6.4 Attempt to actuate the buttons and see if they are indicated on the LED display. Take note of the operation of the status monitor and the waveforms with respect to the indicated touch threshold. Now fill in the table on the next page of the lab sheet following the steps below to tune the channels Step 6.5 Step 6.6 Step 6.7 Step 6.8 Step 6.9 Column 1 - Fill in the value of Cref without touching any buttons, do this for all sensor channels Column 2 - For each sensor channel estimate the p-p noise. You can do this by looking at the numbers that or scrolling or you can use the zoom and center buttons until the p-p variation fits into the window and take the window high limit window low limit. (This is not critical so don t spend too much time) Column 3 - Touch the buttons are connected to that sensor input. Note the delta counts that occur. Complete column 3 with the highest delta touch that occurs for any of the buttons that are connected to that input (Try to touch the middle of the button with a consistent pressure) Column 4 Touch all the buttons that are not connected to that sensor input. Note the delta counts that occur. Complete column 3 with the highest delta touch that occurs for any of the buttons that are not connected to that input (Touch any portions of the board that should not activate a touch) Calculate the new thresholds A good starting point for thresholds will be Capacitive Touch Lab Page 13 of 14
0.6 * Touch delta (column3) + ½ noise counts (Column2) + Off key delta (Column4) Step 6.10 The hysteresis value can be derived by taking ½ to ¾ of the noise counts column Step 6.11 With new thresholds calculated go back and modify the values in Workbench using the setup parameters table and file to include new values for thresholds and hysteresis. Then check the new operation CH # Reference P-P Noise Direct Touch Indirect Touch Calculated Thresholds Calculated Hysteresis Step 6.12 Returning to Workbench, open the Setup Parameters tab and let it auto-fill with the current board parameters Step 6.13 Enter the new Calculate Thresholds and Calculated Hysteresis values in the appropriate columns for each channel Step 6.14 Write back the values to the device memory using the Write->To Device button Step 6.15 Click OK to when the dialog box completes the download process to the device. Step 6.16 Using the tabs switch the display back to the Status Monitor display within Workbench Step 6.17 Click the Start button to begin the graphical display. You will see that the CTHR values are updated. Step 6.18 Test your new settings and see how they function. END OF LAB Capacitive Touch Lab Page 14 of 14