From e9a73bbb3c14af340999f70146747787785f4fee Mon Sep 17 00:00:00 2001
From: Tim Redfern <tim@eclectronics.org>
Date: Mon, 19 Dec 2011 18:20:33 +0000
Subject: initial commit

---
 electic_streaming2560/main.cpp | 80 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 80 insertions(+)
 create mode 100644 electic_streaming2560/main.cpp

(limited to 'electic_streaming2560/main.cpp')

diff --git a/electic_streaming2560/main.cpp b/electic_streaming2560/main.cpp
new file mode 100644
index 0000000..71c276e
--- /dev/null
+++ b/electic_streaming2560/main.cpp
@@ -0,0 +1,80 @@
+extern "C" void __cxa_pure_virtual(void); //for C++ defines
+
+/*
+Electric data access template
+
+TJR 191011
+
+Uses Arduino c++ libraries in vanilla AVR environment
+
+Explanation
+http://www.johnhenryshammer.com/WOW2/pagesHowTo/atmelPage.php#index
+
+*/
+#define SAMPLES 512 //size of ram buffer
+#define PACKETSIZE 320 //size of output packet
+
+#include <WProgram.h> //import main Arduino header file
+
+
+byte dd[SAMPLES];  // ram buffer
+int loopCount=0;
+int sample=0;
+
+void fill_sinewave(){
+    /*
+    sample data to stream
+    the vital thing is that its possible to distinguish the end of a packet
+
+    here the data is in the range 1-255 and a 0 denotes the end of the packet
+    */
+  float pi = 3.141592;
+  float fcnt=0;
+  float fd;
+  float dx=2 * pi / SAMPLES;                    // fill the 512 byte bufferarry
+  int bb;
+    for (int i = 0; i <SAMPLES ; i++){      // with  50 periods sinewawe
+    fd= 127*sin(fcnt);                // fundamental tone
+    fcnt=fcnt+dx;                     // in the range of 0 to 2xpi  and 1/512 increments
+    bb=128+fd;                        // add dc offset to sinewawe
+    dd[i]=bb;                        // write value into array
+  }
+}
+
+int main(){
+
+    //init(); -- init Arduino library - delay, PWM setup messes with timers, millis(), micros() etc don't work without it
+    fill_sinewave();
+    Serial.begin(115200);
+
+    DDRB |= (1 << 5); // port B bit 6 = arduino pin 13
+    PORTB = (1 << 5); //turn on to start
+    TCCR1B |= (1 << WGM12); // Configure timer 1 for CTC mode
+    TIMSK1 |= (1 << OCIE1A); // Enable CTC interrupt
+    OCR1A   = 390; // Set CTC compare value: final speed = CPU clocks / prescaler / CTC 15625=1Hz
+    sei(); //  Enable global interrupts
+
+     while(1) {
+        if (Serial.available() > 0) {
+        PORTB ^= (1 << 5);
+        byte in=Serial.read();
+        if (in=='a') {
+            Serial.println("Welcome to electic");
+            TCCR1B |= ((1<<CS10)|(1 << CS12)); // Set up timer at Fcpu/1024
+        }
+      }
+     }
+}
+
+ISR(TIMER1_COMPA_vect)
+{
+    //if (enabled)
+    PORTB ^= (1 << 5);
+    for (int i=0;i<PACKETSIZE;i++) {
+        Serial.write(dd[sample]);
+        sample=(sample+1)%SAMPLES;
+    }
+    Serial.write((byte)0);
+}
+
+
-- 
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