Yann Garcia / SignalGenerator

This library provides a class to generate differents signale wave form. Note that the maximum update rate of 1 MHz, so Fmax = 1MHz / _num_pixels (see UM10360 - Chapter 30: LPC17xx Digital-to-Analog Converter (DAC).

SignalGenerator.h@1:d6cbee8595e0, 2010-11-22 (annotated)

Committer:
Yann
Date:
Mon Nov 22 08:14:22 2010 +0000
Revision:
1:d6cbee8595e0
Parent:
0:40051400cafe 
V0.0.2

Who changed what in which revision?

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Yann 0:40051400cafe 1 /* mbed signal generator implementation using LPC1768 DAC
Yann 0:40051400cafe 2 * Copyright (c) 2010 ygarcia
Yann 0:40051400cafe 3 *
Yann 0:40051400cafe 4 * Permission is hereby granted, free of charge, to any person obtaining a copy
Yann 0:40051400cafe 5 * of this software and associated documentation files (the "Software"), to deal
Yann 0:40051400cafe 6 * in the Software without restriction, including without limitation the rights
Yann 0:40051400cafe 7 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
Yann 0:40051400cafe 8 * copies of the Software, and to permit persons to whom the Software is
Yann 0:40051400cafe 9 * furnished to do so, subject to the following conditions:
Yann 0:40051400cafe 10 *
Yann 0:40051400cafe 11 * The above copyright notice and this permission notice shall be included in
Yann 0:40051400cafe 12 * all copies or substantial portions of the Software.
Yann 0:40051400cafe 13 *
Yann 0:40051400cafe 14 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
Yann 0:40051400cafe 15 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
Yann 0:40051400cafe 16 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
Yann 0:40051400cafe 17 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
Yann 0:40051400cafe 18 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
Yann 0:40051400cafe 19 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
Yann 0:40051400cafe 20 * THE SOFTWARE.
Yann 0:40051400cafe 21 */
Yann 0:40051400cafe 22
Yann 0:40051400cafe 23 #if !defined(__SIGNALGERNERATOR_H__)
Yann 0:40051400cafe 24 #define __SIGNALGERNERATOR_H__
Yann 0:40051400cafe 25
Yann 0:40051400cafe 26 #include "Debug.h"
Yann 0:40051400cafe 27
Yann 1:d6cbee8595e0 28 /** This class provides methods to generate differents signale wave form. V0.0.0.2
Yann 0:40051400cafe 29 *
Yann 0:40051400cafe 30 * Note that the maximum update rate of 1 MHz, so Fmax = 1MHz / _num_pixels
Yann 0:40051400cafe 31 *
Yann 0:40051400cafe 32 * Note that Vout is given by the relation below (UM10360 - Table 537. D/A Pin Description):
Yann 0:40051400cafe 33 * Vout = VALUE * ((Vrefp - Vrefn) / 1024) + Vrefn
Yann 0:40051400cafe 34 * in which:
Yann 0:40051400cafe 35 * - Vrefp: tied to VDD (e.g. 3.3V)
Yann 0:40051400cafe 36 * - Vrefn: tied to Vss
Yann 0:40051400cafe 37 * @see UM10360 - Chapter 30: LPC17xx Digital-to-Analog Converter (DAC)
Yann 0:40051400cafe 38 * @remark This class was validated with Tektronix TDS2014 oscilloscope
Yann 0:40051400cafe 39 * @author Yann Garcia (Don't hesitate to contact me: garcia.yann@gmail.com)
Yann 0:40051400cafe 40 * References:
Yann 0:40051400cafe 41 * - http://fabrice.sincere.pagesperso-orange.fr/cm_electronique/projet_pic/gbf/gbf.htm
Yann 0:40051400cafe 42 * @todo 1) Enhance comments 2) Add support of user-defined signal in byte array format
Yann 0:40051400cafe 43 */
Yann 0:40051400cafe 44 class SignalGenerator
Yann 0:40051400cafe 45 {
Yann 0:40051400cafe 46 public:
Yann 0:40051400cafe 47 /** List of supported signals
Yann 0:40051400cafe 48 */
Yann 0:40051400cafe 49 enum SignalGeneratorType {
Yann 0:40051400cafe 50 SquareSignal = 0, //<! Square signal (50% duty cycle)
Yann 0:40051400cafe 51 TriangleSignal = 1, //<! Triangle signal
Yann 0:40051400cafe 52 SawtoothSignal = 2, //<! Sawtooth signal
Yann 0:40051400cafe 53 ReverseSawtoothSignal = 3, //<! Reversed sawtooth signal
Yann 0:40051400cafe 54 SinusSignal = 4 //<! Sinusoidal signal
Yann 0:40051400cafe 55 }; // End of SignalGeneratorType enum
Yann 0:40051400cafe 56 public:
Yann 0:40051400cafe 57 /** Default ctor
Yann 0:40051400cafe 58 *
Yann 0:40051400cafe 59 * Initialize the internal datas. Default values are:
Yann 0:40051400cafe 60 * - signal type: SquareSignal
Yann 0:40051400cafe 61 * - frequency: 1000Hz
Yann 0:40051400cafe 62 * - # of pixels is fixed, _twait is adjusted
Yann 0:40051400cafe 63 *
Yann 0:40051400cafe 64 * @param p_outPort: Pin name of the Analog out port (e.g. p18 for LPC1768)
Yann 0:40051400cafe 65 */
Yann 0:40051400cafe 66 SignalGenerator(PinName p_outPort);
Yann 0:40051400cafe 67 /** Default dtor
Yann 0:40051400cafe 68 *
Yann 0:40051400cafe 69 * Free resources
Yann 0:40051400cafe 70 */
Yann 0:40051400cafe 71 virtual ~SignalGenerator();
Yann 0:40051400cafe 72
Yann 0:40051400cafe 73 /** Set the frequency of the signal.
Yann 0:40051400cafe 74 *
Yann 0:40051400cafe 75 * @param p_signalType: Signal type. Default value is square signal
Yann 0:40051400cafe 76 * @param p_frequency: Signal frequency. Default value is 1000Hz
Yann 0:40051400cafe 77 * @param p_num_pixels: Number of pixels ber period. Default value is 64
Yann 0:40051400cafe 78 * @see UM10360 - Chapter 30: LPC17xx Digital-to-Analog Converter (DAC)
Yann 0:40051400cafe 79 * @code
Yann 0:40051400cafe 80 * // Prepare a sinus signal at 500Hz
Yann 0:40051400cafe 81 * signal.SetSignalFrequency(SignalGenerator::SinusSignal,500);
Yann 0:40051400cafe 82 * // Launch execution
Yann 0:40051400cafe 83 * signal.BeginRunAsync();
Yann 0:40051400cafe 84 * // Here signal generation is running. Use Led or oscilloscope to vizualize output
Yann 0:40051400cafe 85 * printf("Press any key to terminate");
Yann 0:40051400cafe 86 * getchar();
Yann 0:40051400cafe 87 * // Terminate execution
Yann 0:40051400cafe 88 * signal.EndRunAsync();
Yann 0:40051400cafe 89 * @endcode
Yann 0:40051400cafe 90 */
Yann 0:40051400cafe 91 void SetSignalFrequency(SignalGenerator::SignalGeneratorType p_signalType = SignalGenerator::SquareSignal, int p_frequency = 1000, int p_num_pixels = 64);
Yann 0:40051400cafe 92 /** Generate the signal in synchrnous mode
Yann 0:40051400cafe 93 *
Yann 0:40051400cafe 94 * @see Stop() method
Yann 0:40051400cafe 95 */
Yann 0:40051400cafe 96 void Run();
Yann 0:40051400cafe 97 /** Method called to terminate synchronous running mode
Yann 0:40051400cafe 98 */
Yann 0:40051400cafe 99 void Stop();
Yann 0:40051400cafe 100 /** Method called to prepare an asynchronous running mode
Yann 0:40051400cafe 101 *
Yann 0:40051400cafe 102 * @return 0 on success, -1 if _twait less that 7us. On error, you shall use synchronous method
Yann 0:40051400cafe 103 */
Yann 0:40051400cafe 104 int BeginRunAsync();
Yann 0:40051400cafe 105 /** Method called to launch the asynchronous running mode
Yann 0:40051400cafe 106 */
Yann 0:40051400cafe 107 void RunAsync();
Yann 0:40051400cafe 108 /** Method called to terminate asynchronous running mode
Yann 0:40051400cafe 109 */
Yann 0:40051400cafe 110 void EndRunAsync();
Yann 0:40051400cafe 111
Yann 0:40051400cafe 112 SignalGenerator& operator =(const bool& p_mode);
Yann 0:40051400cafe 113 SignalGenerator& operator =(const int& p_frequency);
Yann 0:40051400cafe 114 SignalGenerator& operator =(const SignalGenerator::SignalGeneratorType& p_signalType);
Yann 0:40051400cafe 115 private:
Yann 0:40051400cafe 116 /** Set the signal type to generate and build the lookup table according to the signal frequency.
Yann 0:40051400cafe 117 */
Yann 0:40051400cafe 118 void PrepareSignal();
Yann 0:40051400cafe 119 /** Build the lookup table for a square signal according to the signal frequency.
Yann 0:40051400cafe 120 *
Yann 0:40051400cafe 121 * Note that the duty cycle is 50%. For different values, please refer to PwmOut class
Yann 0:40051400cafe 122 */
Yann 0:40051400cafe 123 void PrepareSquareSignal();
Yann 0:40051400cafe 124 /** Build the lookup table for a triangle signal according to the signal frequency.
Yann 0:40051400cafe 125 */
Yann 0:40051400cafe 126 void PrepareTriangleSignal();
Yann 0:40051400cafe 127 /** Build the lookup table for a reverse sawtooth signal according to the signal frequency.
Yann 0:40051400cafe 128 */
Yann 0:40051400cafe 129 void PrepareSawtoothSignal();
Yann 0:40051400cafe 130 /** Build the lookup table for a sawtooth sinal according to the signal frequency.
Yann 0:40051400cafe 131 */
Yann 0:40051400cafe 132 void PrepareReverseSawtoothSignal();
Yann 0:40051400cafe 133 /** Build the lookup table for a 'sinus' sinal according to the signal frequency.
Yann 0:40051400cafe 134 */
Yann 0:40051400cafe 135 void PrepareSinusSignal();
Yann 0:40051400cafe 136 private:
Yann 0:40051400cafe 137 SignalGenerator::SignalGeneratorType _signalType; //<! Signal selected - Default value is SquareSignal
Yann 0:40051400cafe 138 int _frequency; // Required frequency of the signal
Yann 0:40051400cafe 139 float *_values; //<! Pointer to the array of calculated values for the selected signal
Yann 0:40051400cafe 140 int _num_pixels; // <! Number of calculated points, this is the _values length
Yann 0:40051400cafe 141 float _twait; //<! Time between each changes of the analog output
Yann 0:40051400cafe 142 bool _mode; //<! # of pixels is fixed (128 pixels)
Yann 0:40051400cafe 143 AnalogOut _out; //<! Analog out pin of the LPC1768
Yann 0:40051400cafe 144 bool _stop; //<! Set to tru to stop the signal generation
Yann 0:40051400cafe 145 int _asynckCounter; //<! Index on _values when asynchronous run is used
Yann 0:40051400cafe 146 Ticker _asyncTicker; //<! Ticker to ipdate DAC when asynchronous run is used
Yann 0:40051400cafe 147 DigitalOut _debugLed; //<! For debug with oscilloscope purpose
Yann 0:40051400cafe 148 }; // End of class SignalGenerator
Yann 0:40051400cafe 149
Yann 0:40051400cafe 150 #endif // __SIGNALGERNERATOR_H__