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Diff: bx-adc.h
- Revision:
- 1:82bc25a7b68b
--- /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; +}; +