plugins: A simple signal generator

Listens on a configurable SUT's global variable.
On read access a signal pattern value is calculated and sent back
to the SUT.

Currently, only a superimposable sine wave signal form is implemented.
Further signal forms can be implemented by inheriting from the
abstract SignalForm class.

Change-Id: I2e6cf49cd44797999691c9e9cf0c54dd3c96875e

src/plugins/signalgenerator/SignalGenerator.cc

@@ -0,0 +1,63 @@
+#include "SignalGenerator.hpp"
+#include "sal/Listener.hpp"
+#include "sal/Memory.hpp"
+
+using namespace std;
+using namespace fail;
+
+bool SignalGenerator::run()
+{
+    m_log << "Signalgenerator started. @ " << m_symbol << std::endl;
+
+    MemoryManager& mm = simulator.getMemoryManager();
+    MemReadListener l_mem(m_symbol.getAddress());
+
+    /**
+     * for EZS we currently use 8bit ADCs. 
+     * @todo Make more versatile for future use.
+     */
+    uint8_t value;
+
+    while (true) {
+        simulator.addListenerAndResume(&l_mem);
+        value = handleEvent();
+        mm.setBytes(m_symbol.getAddress(), sizeof(value), &value);
+    }
+    return true;
+}
+
+uint8_t SignalGenerator::handleEvent(void)
+{
+    double val = m_signal->calculate();
+    // Scale to uint8: 0 .. 255
+    val = val * 127; // -1: -127 .. +1:  +127
+    val = val + 127; // -127: 0 .. +127 : 254
+    return (uint8_t) val;
+}
+
+
+
+Sine::Sine(const SineParams_t param) {
+    m_params.push_back(param);
+}
+
+double Sine::calculate() const {
+    simtime_t tps = ticksPerSecond();
+    if(tps == 0){
+      // Simulator speed not valid.
+      return 0;
+    }
+
+    // Get simulation time in seconds.
+    double sec = (double)simulator.getTimerTicks() / tps;
+
+    // Sum up all sine waves
+    double val = 0;
+    for(Sine::SineParamsList_t::const_iterator it = m_params.begin(); 
+                it != m_params.end(); it++)
+    {
+      val += it->amplitude * sinus(it->freq_in_hz, sec);
+    }
+    return val;
+}
+