Revision 2:54e9d9ddc350, committed 2014-02-08

Comitter:

ollie8

Date:

Sat Feb 08 13:31:51 2014 +0000

Parent:

1:179b46a0165e

Commit message:

DigiPot can now be used in linear and log modes.

Changed in this revision

diff -r 179b46a0165e -r 54e9d9ddc350 DigiPot.cpp
--- a/DigiPot.cpp	Sat Jan 25 21:05:15 2014 +0000
+++ b/DigiPot.cpp	Sat Feb 08 13:31:51 2014 +0000
@@ -1,23 +1,47 @@
 #include "DigiPot.h"
-#include "math.h"
+#include <math.h>
 
 #define POT_0 0x00
 #define POT_1 0x10
+#define MAX 129.0
+#define MIN 0
+#define MAX_P 100
+#define BASE 10.0
+#define ROUND 0.5
 
-DigiPot::DigiPot(PinName miso, PinName mosi, PinName clk, PinName cs) {
+DigiPot::DigiPot(PinName miso, PinName mosi, PinName clk, PinName cs, Mode mode) {
     chsel = new DigitalOut(cs);
     spi = new SPI(mosi, miso, clk);
+    this->mode = mode;
     spi->format(8,0); 
     spi->frequency(1000000);
     level = 0x00;
+    percent = 0x00;
+    scale = log10(MAX);
 }
 
 void DigiPot::increment() {
-    setLevel(level++);
+    if (mode == LINEAR) {
+        if (level < MAX) {
+            setLevel(level++);    
+        }
+    } else {
+        if (percent < MAX_P) {
+            setLevel(round(pow(BASE, ((scale/MAX_P)*percent++))));
+        }        
+    }
 }
 
 void DigiPot::decrement() {
-    setLevel(level--);
+    if (mode == LINEAR) {
+        if (level > MIN) {
+            setLevel(level--);    
+        }
+    } else {
+        if (percent > MIN) {
+            setLevel(round(pow(BASE, ((scale/MAX_P)*percent--))));
+        }
+    }
 }
 
 void DigiPot::setLevel(unsigned char level) {
@@ -42,4 +66,8 @@
 
 unsigned char DigiPot::getLevel() {
     return level;
-}
\ No newline at end of file
+}
+
+unsigned char DigiPot::round(double value) {
+    return (unsigned char) floor(value+ROUND);    
+}

diff -r 179b46a0165e -r 54e9d9ddc350 DigiPot.h
--- a/DigiPot.h	Sat Jan 25 21:05:15 2014 +0000
+++ b/DigiPot.h	Sat Feb 08 13:31:51 2014 +0000
@@ -3,10 +3,14 @@
 
 #include <mbed.h>
 
+enum Mode {
+    LINEAR, LOGARITHMIC    
+};
+
 class DigiPot {
 
     public:    
-        DigiPot(PinName miso, PinName mosi, PinName clk, PinName cs);
+        DigiPot(PinName miso, PinName mosi, PinName clk, PinName cs, Mode mode);
         void increment();
         void decrement();
         void setLevel(unsigned char);
@@ -17,6 +21,10 @@
         SPI *spi;
         DigitalOut *chsel;
         unsigned char level;
+        unsigned char percent;
+        Mode mode;
+        double scale;
+        unsigned char round(double);
 };
 
 #endif
\ No newline at end of file