updates

M0_Simple_Synth_04/README.md

@@ -2,4 +2,35 @@
 
 This is just a different way to do the LFO.
 
-Basically, rather than changing the interrupt time, we speed up the timer and use a counter to tick off our actual interrupt code.
+Basically, rather than changing the interrupt time, we speed up the timer and use a counter to tick off our actual interrupt code.
+
+This sketch is pretty simple once you strip out the boiler plate.
+
+The Interrupt is based on Timer 4.
+
+The timer has a prescaler of 1024 which brings the timer down to  48MHz/1024 = 46.875kHz.
+
+In addition, we are setting the compare to 500
+
+    TC4->COUNT16.CC[0].reg = 500;   // Set the TC4 CC0 register as the TOP value in match frequency mode
+
+So that brings our interrupt to 46875/500 = 93.75 hz
+
+Now....on top of that, our code is only flipping bits when the counter is reached
+
+    if (counter > counterCompare) {
+      if (state % 2 == 0) {
+        strip.setPixelColor(0, 0, 0, 0); //set the pixel colors
+      } else {
+        strip.setPixelColor(0, 0xFF, 0, 0); //set the pixel colors
+      }
+      strip.show();
+      state++;
+      counter = 0;
+    }
+    counter++;
+
+If the counter was 50, then we would have a frequency of 93.75 / ( 2 * 50) = 9.375 hz
+
+If the counter was 100, then we would have a frequency of 93.75 / ( 2 * 100) = 4.688 hz
+( An octave! )

M0_Simple_Synth_05/README.md

@@ -0,0 +1,10 @@
+# M0_Simple_Synth_0
+
+Nand Synth
+
+So this is an approximation of the following circuit
+
+
+
+
+![Capture1](https://github.com/robstave/trinketM0Synth/blob/master/M0_Simple_Synth_05/images/oneMinusLogPNG.PNG)