Diff: bx-adc.h

Revision:

1:82bc25a7b68b

diff -r 68c173249c01 -r 82bc25a7b68b bx-adc.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/bx-adc.h	Tue Jun 03 15:53:55 2014 +0000
@@ -0,0 +1,117 @@
+#include "mbed.h"
+#include "pinmap.h"
+ 
+
+ 
+ /** A class similar to AnalogIn, only faster, for LPC1768, LPC408X and KLxx
+ *
+ * AnalogIn does a single conversion when you read a value (actually several conversions and it takes the median of that).
+ * This library runns the ADC conversion automatically in the background.
+ * When read is called, it immediatly returns the last sampled value.
+ *
+ * LPC1768 / LPC4088
+ * Using more ADC pins in continuous mode will decrease the conversion rate (LPC1768:200kHz/LPC4088:400kHz).
+ * If you need to sample one pin very fast and sometimes also need to do AD conversions on another pin,
+ * you can disable the continuous conversion on that ADC channel and still read its value.
+ *
+ * KLXX
+ * Multiple Fast instances can be declared of which only ONE can be continuous (all others must be non-continuous).
+ *
+ * When continuous conversion is disabled, a read will block until the conversion is complete
+ * (much like the regular AnalogIn library does).
+ * Each ADC channel can be enabled/disabled separately.
+ *
+ * IMPORTANT : It does not play nicely with regular AnalogIn objects, so either use this library or AnalogIn, not both at the same time!!
+ *
+ * Example for the KLxx processors:
+ * @code
+ * // Print messages when the AnalogIn is greater than 50%
+ *
+ * #include "mbed.h"
+ *
+ * FastAnalogIn temperature(PTC2); //Fast continuous sampling on PTC2
+ * FastAnalogIn speed(PTB3, 0);    //Fast non-continuous sampling on PTB3
+ *
+ * int main() {
+ *     while(1) {
+ *         if(temperature > 0.5) {
+ *             printf("Too hot! (%f) at speed %f", temperature.read(), speed.read());
+ *         }
+ *     }
+ * }
+ * @endcode
+ * Example for the LPC1768 processor:
+ * @code
+ * // Print messages when the AnalogIn is greater than 50%
+ *
+ * #include "mbed.h"
+ *
+ * FastAnalogIn temperature(p20);
+ *
+ * int main() {
+ *     while(1) {
+ *         if(temperature > 0.5) {
+ *             printf("Too hot! (%f)", temperature.read());
+ *         }
+ *     }
+ * }
+ * @endcode
+*/
+class FastAnalogIn {
+ 
+public:
+     /** Create a FastAnalogIn, connected to the specified pin
+     *
+     * @param pin AnalogIn pin to connect to
+     * @param enabled Enable the ADC channel (default = true)
+     */
+    FastAnalogIn( PinName pin, bool enabled = true );
+    
+    ~FastAnalogIn( void )
+    {
+        disable();
+    }
+    
+    /** Enable the ADC channel
+    *
+    * @param enabled Bool that is true for enable, false is equivalent to calling disable
+    */
+    void enable(bool enabled = true);
+    
+    /** Disable the ADC channel
+    *
+    * Disabling unused channels speeds up conversion in used channels. 
+    * When disabled you can still call read, that will do a single conversion (actually two since the first one always returns 0 for unknown reason).
+    * Then the function blocks until the value is read. This is handy when you sometimes needs a single conversion besides the automatic conversion
+    */
+    void disable( void );
+    
+    /** Returns the raw value
+    *
+    * @param return Unsigned integer with converted value
+    */
+    unsigned short read_u16( void );
+    
+    /** Returns the scaled value
+    *
+    * @param return Float with scaled converted value to 0.0-1.0
+    */
+    float read( void )
+    {
+        unsigned short value = read_u16();
+        return (float)value * (1.0f/65535.0f);
+    }
+    
+    /** An operator shorthand for read()
+    */
+    operator float() {
+        return read();
+    }
+ 
+    
+private:
+    bool running;    
+    char ADCnumber;
+    uint32_t *datareg;
+};
+