1 | /*
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2 | Digital Pot Control
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3 |
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4 | This example controls an Analog Devices AD5206 digital potentiometer.
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5 | The AD5206 has 6 potentiometer channels. Each channel's pins are labeled
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6 | A - connect this to voltage
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7 | W - this is the pot's wiper, which changes when you set it
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8 | B - connect this to ground.
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9 |
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10 | The AD5206 is SPI-compatible,and to command it, you send two bytes,
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11 | one with the channel number (0 - 5) and one with the resistance value for the
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12 | channel (0 - 255).
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13 |
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14 | The circuit:
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15 | * All A pins of AD5206 connected to +5V
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16 | * All B pins of AD5206 connected to ground
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17 | * An LED and a 220-ohm resisor in series connected from each W pin to ground
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18 | * CS - to digital pin 10 (SS pin)
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19 | * SDI - to digital pin 11 (MOSI pin)
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20 | * CLK - to digital pin 13 (SCK pin)
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21 |
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22 | created 10 Aug 2010
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23 | by Tom Igoe
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24 |
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25 | Thanks to Heather Dewey-Hagborg for the original tutorial, 2005
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26 |
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27 | */
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28 |
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29 |
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30 | // inslude the SPI library:
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31 | #include <SPI.h>
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32 |
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33 |
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34 | // set pin 10 as the slave select for the digital pot:
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35 | const int slaveSelectPin = 10;
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36 |
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37 | void setup() {
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38 | // set the slaveSelectPin as an output:
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39 | pinMode (slaveSelectPin, OUTPUT);
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40 | // initialize SPI:
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41 | SPI.begin();
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42 | }
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43 |
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44 | void loop() {
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45 | // go through the six channels of the digital pot:
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46 | for (int channel = 0; channel < 6; channel++) {
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47 | // change the resistance on this channel from min to max:
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48 | for (int level = 0; level < 255; level++) {
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49 | digitalPotWrite(channel, level);
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50 | delay(10);
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51 | }
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52 | // wait a second at the top:
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53 | delay(100);
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54 | // change the resistance on this channel from max to min:
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55 | for (int level = 0; level < 255; level++) {
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56 | digitalPotWrite(channel, 255 - level);
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57 | delay(10);
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58 | }
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59 | }
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60 |
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61 | }
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62 |
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63 | void digitalPotWrite(int address, int value) {
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64 | // take the SS pin low to select the chip:
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65 | digitalWrite(slaveSelectPin, LOW);
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66 | // send in the address and value via SPI:
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67 | SPI.transfer(address);
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68 | SPI.transfer(value);
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69 | // take the SS pin high to de-select the chip:
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70 | digitalWrite(slaveSelectPin, HIGH);
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71 | }
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