Provide the ability to choose a timer for megaavr

Signed-off-by: Vladyslav Arzhanov <[email protected]>

Author: vladyslav-arzhanov

src/megaavr/ServoTimers.h

@@ -26,23 +26,18 @@
 
 #include <avr/io.h>
 
-//#define USE_TIMERB1        // interferes with PWM on pin 3
-#define USE_TIMERB2        // interferes with PWM on pin 11
-//#define USE_TIMERB0        // interferes with PWM on pin 6
-
 #if !defined(USE_TIMERB1) && !defined(USE_TIMERB2) && !defined(USE_TIMERB0)
-    # error "No timers allowed for Servo"
-    /* Please uncomment a timer above and rebuild */
+    #define USE_TIMERB2  // default timer
 #endif
 
 static volatile TCB_t* _timer =
-#if defined(USE_TIMERB0)
+#if defined(USE_TIMERB0) // interferes with PWM on pin 6
 &TCB0;
 #endif
-#if defined(USE_TIMERB1)
+#if defined(USE_TIMERB1) // interferes with PWM on pin 3
 &TCB1;
 #endif
-#if defined(USE_TIMERB2)
+#if defined(USE_TIMERB2) // interferes with PWM on pin 11
 &TCB2;
 #endif