Chris Taylor / SignalGenerator

Provides a simple way to generate complex square wave signals on any available pin. In addition the SignalGenerator can generate a carrier wave which is useful when generating IR signals to control electronic devices like a TV etc. The signal generation can be carried out either synchronously or asynchronously. In the case of synchronous signal generation all interrupts can optionally be disabled to improve timing accuracy.

SignalGenerator.h@4:64d2d834341b, 2014-09-14 (annotated)

Committer:
taylorza
Date:
Sun Sep 14 05:36:57 2014 +0000
Revision:
4:64d2d834341b
Parent:
3:f30dcc6e8e70 
Added support for asynchronous signal generation

Who changed what in which revision?

UserRevisionLine numberNew contents of line
taylorza 1:4a1bcc41c473 1 ///////////////////////////////////////////////////////////////////////////////
taylorza 1:4a1bcc41c473 2 // Signal Generator
taylorza 1:4a1bcc41c473 3 // Author: Chris Taylor (taylorza)
taylorza 0:b7c65c0d82d3 4 #ifndef __SIGNALGENERATOR_H__
taylorza 0:b7c65c0d82d3 5 #define __SIGNALGENERATOR_H__
taylorza 0:b7c65c0d82d3 6
taylorza 0:b7c65c0d82d3 7 /** Simplifies generation of a high frequency signal on any pin with optional support for a carrier frequency.
taylorza 0:b7c65c0d82d3 8 */
taylorza 0:b7c65c0d82d3 9 class SignalGenerator
taylorza 0:b7c65c0d82d3 10 {
taylorza 0:b7c65c0d82d3 11 public:
taylorza 0:b7c65c0d82d3 12 /** Create a SignalGenerator tied to the specified pin. */
taylorza 0:b7c65c0d82d3 13 SignalGenerator(PinName pin);
taylorza 0:b7c65c0d82d3 14
taylorza 4:64d2d834341b 15 /** Clean up the SignalGenerator data. */
taylorza 4:64d2d834341b 16 ~SignalGenerator();
taylorza 4:64d2d834341b 17
taylorza 0:b7c65c0d82d3 18 /** Set the state of the pin associated with the SignalGenerator. */
taylorza 0:b7c65c0d82d3 19 void set(bool pinState);
taylorza 0:b7c65c0d82d3 20
taylorza 4:64d2d834341b 21 /** Generates the square wave signal on the pin associated with the SignalGenerator.
taylorza 0:b7c65c0d82d3 22 * @param initialState Defines the initial state of the signal pin
taylorza 0:b7c65c0d82d3 23 * @param timingBuffer Specificies the wime periods in microseconds before the signal pin changes state
taylorza 0:b7c65c0d82d3 24 * @param bufferCount The count of transition times passed in the timingBuffer
taylorza 4:64d2d834341b 25 * @param disableInterrupts If true disables interrupts during the generation of the signal
taylorza 0:b7c65c0d82d3 26 * @param lastStateHoldTime The time in microseconds that the last state is held
taylorza 0:b7c65c0d82d3 27 * @param carrierFrequency The carrier frequency in Hz
taylorza 0:b7c65c0d82d3 28 */
taylorza 1:4a1bcc41c473 29 void set(
taylorza 1:4a1bcc41c473 30 bool initialState,
taylorza 1:4a1bcc41c473 31 uint32_t timingBuffer[],
taylorza 1:4a1bcc41c473 32 uint16_t bufferCount,
taylorza 4:64d2d834341b 33 bool disableInterrupts,
taylorza 1:4a1bcc41c473 34 uint32_t lastStateHoldTime = 0,
taylorza 2:b2a449bd787f 35 int32_t carrierFrequency = -1);
taylorza 4:64d2d834341b 36
taylorza 4:64d2d834341b 37 /** Asynchronously generates the square wave signal on the pin associated with the SignalGenerator.
taylorza 4:64d2d834341b 38 * @param initialState Defines the initial state of the signal pin
taylorza 4:64d2d834341b 39 * @param timingBuffer Specificies the wime periods in microseconds before the signal pin changes state
taylorza 4:64d2d834341b 40 * @param bufferCount The count of transition times passed in the timingBuffer
taylorza 4:64d2d834341b 41 * @param repeat If true the signal generation will wrap around to the begining of the timingBuffer after each iteration through the buffer completes.
taylorza 4:64d2d834341b 42 * @note To stop the asynchronous signal you can call any of the non-async set commands to set the pin to a final state.
taylorza 4:64d2d834341b 43 */
taylorza 4:64d2d834341b 44 void setAsync(
taylorza 4:64d2d834341b 45 bool initialState,
taylorza 4:64d2d834341b 46 uint32_t timingBuffer[],
taylorza 4:64d2d834341b 47 uint16_t bufferCount,
taylorza 4:64d2d834341b 48 bool repeat);
taylorza 1:4a1bcc41c473 49
taylorza 0:b7c65c0d82d3 50 private:
taylorza 4:64d2d834341b 51 void asyncStep();
taylorza 4:64d2d834341b 52 void stopAsync();
taylorza 4:64d2d834341b 53
taylorza 4:64d2d834341b 54 private:
taylorza 4:64d2d834341b 55 DigitalOut _pin;
taylorza 4:64d2d834341b 56 Timeout *_pTicker;
taylorza 4:64d2d834341b 57 uint32_t *_pInternalTimingBuffer;
taylorza 4:64d2d834341b 58 uint16_t _bufferCount;
taylorza 4:64d2d834341b 59 uint16_t _bufferIndex;
taylorza 4:64d2d834341b 60 bool _repeat;
taylorza 0:b7c65c0d82d3 61 };
taylorza 0:b7c65c0d82d3 62 #endif //__SIGNALGENERATOR_H__