Diff: SignalGenDAC.h

Revision:

0:c1a4c1e9618c

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/SignalGenDAC.h	Mon Dec 05 02:01:53 2022 +0000
@@ -0,0 +1,96 @@
+//
+// Signal Generator DAC Driver
+//
+// Derived from AN10917: Memory to DAC data transfers using the LPC1700's DMA
+//
+// 
+#ifndef SIGNALGENDAC_H
+#define SIGNALGENDAC_H
+
+#include "mbed.h"
+
+#include "SignalGenDefs.h"       // access the waveform mode data type
+
+
+#define SIGNAL_MEM_ENTRIES 2048     // size of the DAC buffer
+
+/// The Signal Generator DAC Driver
+///
+/// This class provides the interface to first configure the DAC hardware characteristics,
+/// and then to define and control the DAC output.
+///
+/// A choice of waveforms is available (Sine, Square, Triangle, Sawtooth, and User Defined.
+///
+/// @todo add support for User Defined waveform.
+///
+/// @code
+/// SignalGenDAC g_signal;            // defaults to LPC1768 mbed module (p18 and 3.3v)
+/// 
+/// g_signal.PrepareWaveform(SG_SINE, 1000, 50, 2.2, 1.5);
+/// g_signal.Start();
+/// wait_ms(1000);
+/// g_signal.Stop();
+/// @endcode
+///
+class SignalGenDAC {
+
+public:
+
+    /// Constructor, which is used to define the hardware
+    /// 
+    /// The default parameters are based on the mbed LPC1768 micro, which has
+    /// AnalogOut on p18 and uses a 3.3v supply for the A/D reference.
+    ///
+    /// @param[in] aout is the analog output pin
+    /// @param[in] minV is based on the A/D low reference voltage (default 0.0)
+    /// @param[in] maxV is based on the A/D high reference voltage (default 3.3)
+    ///
+    SignalGenDAC(PinName aout = p18, float minV = 0.0, float maxV = 3.3);
+
+    /// Destructor
+    ///
+    ~SignalGenDAC();
+
+    /// Create the waveform in the private memory buffer that is used to DMA to the DAC
+    ///
+    /// @param[in] mode defines the waveform: Sine, Square, Triangle, Sawtooth, User
+    /// @param[in] frequency defines the desired frequency
+    /// @param[in] dutycycle defined the duty cycle of the waveform to be created. The value
+    ///             is range limited to 5 to 95 (representing 5 to 95 %).
+    /// @param[in] voltage is the peak-to-peak voltage, and it range limited to 0 to 3.0.
+    /// @param[in] offset is the offset voltage, and is range limited to 0 to 3.0.
+    ///
+    void PrepareWaveform(SG_Waveform mode, float frequency, float dutycycle, float voltage, float offset);
+
+    /// Start the signal, in either a oneshot, or continuous mode.
+    ///
+    /// @param[in] oneShot defaults false, which causes continuous mode. 
+    ///             When set true, one cycle is produced.
+    ///
+    void Start(bool oneShot = false);
+
+    /// Stop the signal, if it is running.
+    ///
+    void Stop(void);
+
+    /// Determine if the signal is running.
+    ///
+    /// @returns true if the signal is running.
+    ///
+    bool isRunning(void) { return isOn; }
+
+private:
+    bool isOn;              // tracks whether the signal is on or off
+    AnalogOut * aout;
+    float frequency;        // signal parameters
+    float dutycycle;
+    float voltage;
+    float offset;
+    float minV;             // Based on the A/D hardware
+    float maxV;             // Based on the A/D hardware
+    /// range limit a value.
+    float rangelimit(float value, float min, float max);
+    int numSamples;         // private container for number of samples
+};
+
+#endif // SIGNALGENDAC_H
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