For example the temperature sensor may be snapped off

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Unformatted text preview: (or EUSART). Connecting a shunt between the bottom two pins (TX and RX) allows the user to transmit and receive serial communication via one pin (jumper between the microcontroller and the TX/RX pin on JP2). © 2005 Microchip Technology Inc. DS51557B-page 15 PICDEMTM Mechatronics Demo Board User’s Guide 1.8.6 SNAP-OFF SENSORS The temperature sensor and light sensor can be snapped off to give greater flexibility in using these sensors. For example, the temperature sensor may be snapped off and moved into a more hostile environment, while keeping the board within sight. Once, snapped off, solder wires of the same length between the adjoining holes (i.e., JP3 and JP4 for the temperature sensor) on the PICDEM Mechatronics Demo Board and the sensor board. 1.8.7 BACK EMF SCALING RESISTORS If choosing to drive your own brushed DC motor with the PICDEM Mechatronics Demo Board at a voltage higher than +5 VDC, the Back EMF must be scaled down into a range of 0-5 VDC. Resistor locations R55 and R56 are provided for this purpose. These locations may be populated with resistors to create a simple voltage divider circuit. TP1 is the output of this voltage divider. See the schematic in Appendix A. “Hardware Schematics” for further clarification. 1.8.8 CURRENT SENSE The output stage of the board incorporates a simple current sensing circuit, which is assessable at J15 (CURRENT SENSE). At this pin, the voltage is equal to current ± 10%. For instance, if a motor is being driven and it is drawing 0.9 amps, the voltage at the header is 0.9 volts (± 10%). DS51557B-page 16 © 2005 Microchip Technology Inc. PICDEM™ Mechatronics 1.8.9 HEADER/JUMPER FUNCTIONS TABLE 1-1: HEADER/JUMPER FUNCTIONS Header/ Jumper # Description J1* Output MOSFET drive pins. J2 Full-bridge drive circuit (Drives 1 and 2): Place three shunts vertically on these pins to create a full-bridge drive circuit incorporating Drives 1 and 2. J3 Full-bridge drive circuit (Drives 3 and 4): Place three shunts vertically on these pins to create a full-bridge drive circuit incorporating Drives 3 and 4. J4* Temperature sensor, light sensor, potentiometers, 32.768 oscillator and switches signal pins. J5* Right-side signal pins of the 20-pin DIP socket (U2, pins 11-20). J6* Left-side signal pins of the 20-pin DIP socket (U2, pins 1-10). J7* Optical interrupter feedback signal pins. J10* Right-side signal pins of the 40-pin DIP socket (U1, pins 21-40). J13* Left-side signal pins of the 40-pin DIP socket (U1, pins 1-20). J14 LED connect pins. J15* Current sense feedback from the drive stage. J16* Back EMF feedback signal pins. JP2 Single-pin serial communication jumper (see Section 1.8.5 “Serial Communication” for details). JP8 Drive circuit voltage selection. See diagram on board. * On these jumpers, the pins are connected in pairs horizontally. This allows one pin to be used for jumping to/from the microcontroller (using a wire jumper) and the other pin for probing the circuit with test equipment. © 2005 Microchip Technology Inc. DS51557B-page 17 PICDEMTM Mechatronics Demo Board User’s Guide NOTES: DS51557B-page 18 © 2005 Microchip Technology Inc. PICDEMTM MECHATRONICS DEMO BOARD USER’S GUIDE Chapter 2. Example Projects 2.1 INTRODUCTION The following projects cover basic mechatronic principles such as reading a sensor, interfacing to a LCD and driving a motor. These projects also provide examples of how to use the various PICmicro® microcontroller peripherals. The projects are presented sequentially so that you will build knowledge as you progress from one project to the next. Those who are new to programming PIC® microcontrollers should pay special attention to the comments in the source code for each of the projects. Though these projects are not intended to teach you the Microchip Assembly language, you will be able to get a good grasp of Microchip’s Assembly language by reading the source code. Microchip has published application notes and other documents covering the applications in each of these projects. These documents can be found on the provided CD-ROM. Any updates to the applicable documents are available on Microchip’s web site. Please reference these documents while exploring each of the projects. Note: © 2005 Microchip Technology Inc. See Section 1.7 “PICDEM™ Mechatronics Setup” for instructions on how to setup the board to its “initial” condition prior to doing projects. DS51557B-page 19 PICDEMTM Mechatronics Demo Board User’s Guide 2.2 LOADING PROJECTS IN MPLAB® IDE The firmware for the projects is arranged in corresponding project folders in the install directory for the PICDEM Mechatronics CD. If you installed the CD in the default directory, the firmware for Project 1 is located in: C:\PICDEM Mechatronics\firmware\Project1 Opening a Project 1. 2. 3. 4. Start MPLAB IDE. In the menu bar choose File -> Open Workspace. Find the project folder. Open the *.mcw file. The project window for Project 1 is shown in Figure 2-1. FIGURE 2-1: 2.3 PROJECT WINDOW EXAMPLE PROJECTS PIC16F917 Projects: • Project 1: Hello World (Light a LED) • Project 2: Dusk Indicator Using the Voltage Comparator • Project 3: Thermome...
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This note was uploaded on 01/29/2014 for the course AA AA taught by Professor Aa during the Winter '10 term at ENS Cachan.

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