commented out 20MHz setup. 3.3Mhz with 6x divisor for the main clock works fine and saves power.

main.c

@@ -9,7 +9,8 @@
  * extracted into separate source files and headers for configuration.
  */
 
-#define F_CPU 2000000UL
+//#define F_CPU 2000000UL
+#define F_CPU 3333333UL
 
 //These defines are mostly useful for when you want you editors LSP server to
 //function correctly.
@@ -46,7 +47,7 @@ static void CLK_DisablePrescaler(void)
 
 int main(int argc, char **argv)
 {
-    CLK_DisablePrescaler();
+    //CLK_DisablePrescaler();
     while(true){
         for(int i = 0; i < GatePulsesQty; i++){
             ZCD_Poll();