Revision 0:7e6a051d1700, committed 2011-03-30

Comitter:

goeckeritz

Date:

Wed Mar 30 15:34:58 2011 +0000

Commit message:

initial upload

Changed in this revision

diff -r 000000000000 -r 7e6a051d1700 TSL2550.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSL2550.cpp	Wed Mar 30 15:34:58 2011 +0000
@@ -0,0 +1,104 @@
+/*
+ * mbed library to use a TAOS TSL2550 Ambient Light Sensor
+ * Copyright (c) 2011 Stefan Goeckeritz, 
+ * RheinAhrCampus Remagen, Suedallee 2, 53424 Remagen
+ * 
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+
+#include "mbed.h"
+#include "TSL2550.h"
+
+#define TSL2550_ADDR 0x72                                                     //hardwired slave address of TSL2550
+#define xpow(x, y) ((long)1 << y)
+
+
+TSL2550::TSL2550 (PinName p_sda, PinName p_scl ) : i2c(p_sda, p_scl) {
+    init();
+}
+
+TSL2550::TSL2550 (I2C& p_i2c) : i2c(p_i2c) { 
+    init();
+}
+
+unsigned short  TSL2550::get_ch0() {
+    return ch0;
+}
+
+unsigned short TSL2550::get_ch1() {
+    return ch1;
+}
+
+double TSL2550::get_lux() {
+    return lux;
+}
+
+void TSL2550::update () {
+    unsigned short c0, c1, s0, s1;
+    int adc0, adc1;
+    double r;
+
+    //read channel 0 and 1
+    ch0 = twi_read(TSL2550_ADDR, 0x43);
+    wait(0.5);
+    ch1 = twi_read(TSL2550_ADDR, 0x83);
+
+    //now compute lux value, if data is valid
+    if((ch0 & 0x80) &&  (ch1 & 0x80))
+    {
+        c0 = (ch0 & ~0x80) >> 4 ;
+        c1 = (ch1 & ~0x80) >> 4 ;
+        s0 = ch0 & ~0xF0 ;
+        s1 = ch1 & ~0xF0 ;
+                
+        //ADC Count Value
+        adc0 = int(16.5 * xpow(2,c0)) + (s0 * xpow(2,c0));
+        adc1 = int(16.5 * xpow(2,c1)) + (s1 * xpow(2,c1));
+        
+        r = (double(adc1) / double(adc0));
+        lux = double(adc0) * 0.46 * exp(-3.13 * r);
+                
+        //give debug information
+        //printf("\n\nZW: c0=%i s0=%i c1=%i s1=%i \n", c0, s0, c1, s1);
+        //printf("ZW: adc0=%i, adc1=%i\n", adc0, adc1);
+    }
+    else
+        printf("TSL2550: ***data not valid ! ***\n");    
+}
+
+void TSL2550::init() {
+    unsigned short i;
+    
+    i = twi_read(TSL2550_ADDR, 0x03);
+    if( i == 0x03 )
+        printf("TSL2550: Init successful\n");
+    else
+        printf("TSL2550: Init ***failed*** !\n");    
+}
+
+unsigned short TSL2550::twi_read (unsigned short id, unsigned short data) {
+    unsigned short i;
+
+    //supply COMMAND byte to slave
+    i2c.start();
+    i2c.write(id);
+    i2c.write(data);
+
+    //demand ANSWER byte from slave    
+    i2c.start();
+    i2c.write(id | 1);
+    i = i2c.read(0);
+    i2c.stop();
+    
+
+    return i;
+}
+
+void TSL2550::twi_write (unsigned short id, unsigned short data) {
+
+    i2c.start();
+    i2c.write(id);
+    i2c.write(data);
+    i2c.stop();
+}
+

diff -r 000000000000 -r 7e6a051d1700 TSL2550.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/TSL2550.h	Wed Mar 30 15:34:58 2011 +0000
@@ -0,0 +1,36 @@
+/*
+ * mbed library to use a TAOS TSL2550 Ambient Light Sensor
+ * Copyright (c) 2011 Stefan Goeckeritz, 
+ * RheinAhrCampus Remagen, Suedallee 2, 53424 Remagen
+ * 
+ * Released under the MIT License: http://mbed.org/license/mit
+ */
+ 
+#ifndef TSL2550_H
+#define TSL2550_H
+
+#include "mbed.h"
+
+class TSL2550 : public Base {
+public:
+    TSL2550(PinName p_sda, PinName p_scl);
+    TSL2550(I2C& p_i2c);
+
+    unsigned short get_ch0();
+    unsigned short get_ch1();    
+    double get_lux();
+    void update();
+
+protected:
+    void init();
+    unsigned short twi_read (unsigned short, unsigned short);
+    void twi_write (unsigned short, unsigned short);
+
+    I2C i2c;
+
+private:
+    double lux;
+    unsigned short ch0, ch1;
+};
+
+#endif
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