From 7bac64c4ac056c88420421ffaed08a36fcbc44d4 Mon Sep 17 00:00:00 2001
From: Tom Igoe <t.igoe@arduino.cc>
Date: Tue, 10 Aug 2010 21:42:26 +0000
Subject: [PATCH] Added AD5206 Digital Potentiometer example to SPI library

---
 .../DigitalPotControl/DigitalPotControl.pde   | 67 +++++++++++++++++++
 1 file changed, 67 insertions(+)
 create mode 100644 libraries/SPI/examples/DigitalPotControl/DigitalPotControl.pde

diff --git a/libraries/SPI/examples/DigitalPotControl/DigitalPotControl.pde b/libraries/SPI/examples/DigitalPotControl/DigitalPotControl.pde
new file mode 100644
index 000000000..54a46051b
--- /dev/null
+++ b/libraries/SPI/examples/DigitalPotControl/DigitalPotControl.pde
@@ -0,0 +1,67 @@
+/*
+  Digital Pot Control
+  
+  This example controls an Analog Devices AD5206 digital potentiometer.
+  The AD5206 has 6 potentiometer channels. Each channel's pins are labeled
+  A - connect this to voltage
+  W - this is the pot's wiper, which changes when you set it
+  B - connect this to ground.
+ 
+ The AD5206 is SPI-compatible,and to command it, you send two bytes, 
+ one with the channel number (0 - 5) and one with the resistance value for the
+ channel (0 - 255).  
+ 
+ The circuit:
+  * All A pins  of AD5206 connected to +5V
+  * All B pins of AD5206 connected to ground
+  * An LED and a 220-ohm resisor in series connected from each W pin to ground
+  * CS - to digital pin 10  (SS pin)
+  * SDI - to digital pin 11 (MOSI pin)
+  * CLK - to digital pin 13 (SCK pin)
+ 
+ created 10 Aug 2010 
+ by Tom Igoe
+ 
+ Thanks to Heather Dewey-Hagborg for the original tutorial, 2005
+ 
+*/
+
+
+// inslude the SPI library:
+#include <SPI.h>
+
+void setup() {
+  // set pin 10 as the slave select for the digital pot:
+  pinMode (10, OUTPUT);
+  // initialize SPI:
+  SPI.begin(); 
+}
+
+void loop() {
+  // go through the six channels of the digital pot:
+  for (int channel = 0; channel < 6; channel++) { 
+    // change the resistance on this channel from min to max:
+    for (int level = 0; level < 255; level++) {
+      digitalPotWrite(channel, level);
+      delay(10);
+    }
+    // wait a second at the top:
+    delay(100);
+    // change the resistance on this channel from max to min:
+    for (int level = 0; level < 255; level++) {
+      digitalPotWrite(channel, 255 - level);
+      delay(10);
+    }
+  }
+
+}
+
+int digitalPotWrite(int address, int value) {
+  // take the SS pin low to select the chip:
+  digitalWrite(10,LOW);
+  //  send in the address and value via SPI:
+  SPI.transfer(address);
+  SPI.transfer(value);
+  // take the SS pin high to de-select the chip:
+  digitalWrite(10,HIGH); 
+}
\ No newline at end of file