diff --git a/hardware/arduino/cores/arduino/Tone.cpp b/hardware/arduino/cores/arduino/Tone.cpp
index 3ea034bf9..8bdc5f771 100755
--- a/hardware/arduino/cores/arduino/Tone.cpp
+++ b/hardware/arduino/cores/arduino/Tone.cpp
@@ -28,7 +28,7 @@ Version Modified By Date     Comments
                     09/11/25 Changed pin toggle method to XOR
                     09/11/25 Fixed timer0 from being excluded
 0006    D Mellis    09/12/29 Replaced objects with functions
-
+0007    M Sproul    10/08/29 Changed #ifdefs from cpu to register
 *************************************************/
 
 #include <avr/interrupt.h>
@@ -36,7 +36,7 @@ Version Modified By Date     Comments
 #include "wiring.h"
 #include "pins_arduino.h"
 
-#if defined(__AVR_ATmega8__)
+#if defined(__AVR_ATmega8__) || defined(__AVR_ATmega128__)
 #define TCCR2A TCCR2
 #define TCCR2B TCCR2
 #define COM2A1 COM21
@@ -66,19 +66,26 @@ volatile long timer2_toggle_count;
 volatile uint8_t *timer2_pin_port;
 volatile uint8_t timer2_pin_mask;
 
-#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+#if defined(TIMSK3)
 volatile long timer3_toggle_count;
 volatile uint8_t *timer3_pin_port;
 volatile uint8_t timer3_pin_mask;
+#endif
+
+#if defined(TIMSK4)
 volatile long timer4_toggle_count;
 volatile uint8_t *timer4_pin_port;
 volatile uint8_t timer4_pin_mask;
+#endif
+
+#if defined(TIMSK5)
 volatile long timer5_toggle_count;
 volatile uint8_t *timer5_pin_port;
 volatile uint8_t timer5_pin_mask;
 #endif
 
 
+// MLS: This does not make sense, the 3 options are the same
 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
 
 #define AVAILABLE_TONE_PINS 1
@@ -133,7 +140,7 @@ static int8_t toneBegin(uint8_t _pin)
     // whereas 16 bit timers are set to either ck/1 or ck/64 prescalar
     switch (_timer)
     {
-#if !defined(__AVR_ATmega8__)
+      #if defined(TCCR0A) && defined(TCCR0B)
       case 0:
         // 8 bit timer
         TCCR0A = 0;
@@ -143,8 +150,9 @@ static int8_t toneBegin(uint8_t _pin)
         timer0_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer0_pin_mask = digitalPinToBitMask(_pin);
         break;
-#endif
+      #endif
 
+      #if defined(TCCR1A) && defined(TCCR1B) && defined(WGM12)
       case 1:
         // 16 bit timer
         TCCR1A = 0;
@@ -154,6 +162,9 @@ static int8_t toneBegin(uint8_t _pin)
         timer1_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer1_pin_mask = digitalPinToBitMask(_pin);
         break;
+      #endif
+
+      #if defined(TCCR2A) && defined(TCCR2B)
       case 2:
         // 8 bit timer
         TCCR2A = 0;
@@ -163,8 +174,9 @@ static int8_t toneBegin(uint8_t _pin)
         timer2_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer2_pin_mask = digitalPinToBitMask(_pin);
         break;
+      #endif
 
-#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+      #if defined(TCCR3A) && defined(TCCR3B) &&  defined(TIMSK3)
       case 3:
         // 16 bit timer
         TCCR3A = 0;
@@ -174,15 +186,27 @@ static int8_t toneBegin(uint8_t _pin)
         timer3_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer3_pin_mask = digitalPinToBitMask(_pin);
         break;
+      #endif
+
+      #if defined(TCCR4A) && defined(TCCR4B) &&  defined(TIMSK4)
       case 4:
         // 16 bit timer
         TCCR4A = 0;
         TCCR4B = 0;
-        bitWrite(TCCR4B, WGM42, 1);
+        #if defined(WGM42)
+          bitWrite(TCCR4B, WGM42, 1);
+        #elif defined(CS43)
+          #warning this may not be correct
+          // atmega32u4
+          bitWrite(TCCR4B, CS43, 1);
+        #endif
         bitWrite(TCCR4B, CS40, 1);
         timer4_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer4_pin_mask = digitalPinToBitMask(_pin);
         break;
+      #endif
+
+      #if defined(TCCR5A) && defined(TCCR5B) &&  defined(TIMSK5)
       case 5:
         // 16 bit timer
         TCCR5A = 0;
@@ -192,7 +216,7 @@ static int8_t toneBegin(uint8_t _pin)
         timer5_pin_port = portOutputRegister(digitalPinToPort(_pin));
         timer5_pin_mask = digitalPinToBitMask(_pin);
         break;
-#endif
+      #endif
     }
   }
 
@@ -258,12 +282,22 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration)
         }
       }
 
-#if !defined(__AVR_ATmega8__)
+#if defined(TCCR0B)
       if (_timer == 0)
+      {
         TCCR0B = prescalarbits;
+      }
       else
 #endif
+#if defined(TCCR2B)
+      {
         TCCR2B = prescalarbits;
+      }
+#else
+      {
+        // dummy place holder to make the above ifdefs work
+      }
+#endif
     }
     else
     {
@@ -278,12 +312,20 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration)
       }
 
       if (_timer == 1)
+      {
+#if defined(TCCR1B)
         TCCR1B = (TCCR1B & 0b11111000) | prescalarbits;
-#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+#endif
+      }
+#if defined(TCCR3B)
       else if (_timer == 3)
         TCCR3B = (TCCR3B & 0b11111000) | prescalarbits;
+#endif
+#if defined(TCCR4B)
       else if (_timer == 4)
         TCCR4B = (TCCR4B & 0b11111000) | prescalarbits;
+#endif
+#if defined(TCCR5B)
       else if (_timer == 5)
         TCCR5B = (TCCR5B & 0b11111000) | prescalarbits;
 #endif
@@ -307,7 +349,7 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration)
     switch (_timer)
     {
 
-#if !defined(__AVR_ATmega8__)
+#if defined(OCR0A) && defined(TIMSK0) && defined(OCIE0A)
       case 0:
         OCR0A = ocr;
         timer0_toggle_count = toggle_count;
@@ -316,27 +358,43 @@ void tone(uint8_t _pin, unsigned int frequency, unsigned long duration)
 #endif
 
       case 1:
+#if defined(OCR1A) && defined(TIMSK1) && defined(OCIE1A)
         OCR1A = ocr;
         timer1_toggle_count = toggle_count;
         bitWrite(TIMSK1, OCIE1A, 1);
+#elif defined(OCR1A) && defined(TIMSK) && defined(OCIE1A)
+        // this combination is for at least the ATmega32
+        OCR1A = ocr;
+        timer1_toggle_count = toggle_count;
+        bitWrite(TIMSK, OCIE1A, 1);
+#endif
         break;
+
+#if defined(OCR2A) && defined(TIMSK2) && defined(OCIE2A)
       case 2:
         OCR2A = ocr;
         timer2_toggle_count = toggle_count;
         bitWrite(TIMSK2, OCIE2A, 1);
         break;
+#endif
 
-#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+#if defined(TIMSK3)
       case 3:
         OCR3A = ocr;
         timer3_toggle_count = toggle_count;
         bitWrite(TIMSK3, OCIE3A, 1);
         break;
+#endif
+
+#if defined(TIMSK4)
       case 4:
         OCR4A = ocr;
         timer4_toggle_count = toggle_count;
         bitWrite(TIMSK4, OCIE4A, 1);
         break;
+#endif
+
+#if defined(OCR5A) && defined(TIMSK5) && defined(OCIE5A)
       case 5:
         OCR5A = ocr;
         timer5_toggle_count = toggle_count;
@@ -356,27 +414,48 @@ void disableTimer(uint8_t _timer)
 {
   switch (_timer)
   {
-#if !defined(__AVR_ATmega8__)
     case 0:
-      TIMSK0 = 0;
+      #if defined(TIMSK0)
+        TIMSK0 = 0;
+      #elif defined(TIMSK)
+        TIMSK = 0; // atmega32
+      #endif
       break;
-#endif
+
+#if defined(TIMSK1) && defined(OCIE1A)
     case 1:
       bitWrite(TIMSK1, OCIE1A, 0);
       break;
+#endif
+
     case 2:
-      bitWrite(TIMSK2, OCIE2A, 0); // disable interrupt
-      TCCR2A = (1 << WGM20);
-      TCCR2B = (TCCR2B & 0b11111000) | (1 << CS22);
-      OCR2A = 0;
+      #if defined(TIMSK2) && defined(OCIE2A)
+        bitWrite(TIMSK2, OCIE2A, 0); // disable interrupt
+      #endif
+      #if defined(TCCR2A) && defined(WGM20)
+        TCCR2A = (1 << WGM20);
+      #endif
+      #if defined(TCCR2B) && defined(CS22)
+        TCCR2B = (TCCR2B & 0b11111000) | (1 << CS22);
+      #endif
+      #if defined(OCR2A)
+        OCR2A = 0;
+      #endif
       break;
-#if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__)
+
+#if defined(TIMSK3)
     case 3:
       TIMSK3 = 0;
       break;
+#endif
+
+#if defined(TIMSK4)
     case 4:
       TIMSK4 = 0;
       break;
+#endif
+
+#if defined(TIMSK5)
     case 5:
       TIMSK5 = 0;
       break;