Pins 5 and 6: controlled by Timer 0
Setting 	Divisor 	Frequency
0x01 	 	1 	 		62500
0x02  		8 	 		7812.5
0x03  		64 	 		976.5625
0x04 	 	256 	 	244.140625
0x05 	 	1024 	 	61.03515625
TCCR0B = TCCR0B & 0b11111000 | <setting>;
Pins 9 and 10: controlled by timer 1
Setting 	Divisor 	Frequency
0x01 	 	1 	 		31250
0x02 	 	8 	 		3906.25
0x03  		64 	 		488.28125
0x04  		256 	 	122.0703125
0x05 	 	1024 	 	30.517578125
TCCR1B = TCCR1B & 0b11111000 | <setting>;
Pins 11 and 3: controlled by timer 2
Setting 	Divisor 	Frequency
0x01 	 	1  			31250
0x02 	 	8 	 		3906.25
0x03  		32  		976.5625
0x04 	 	64 	 		488.28125
0x05 	 	128  		244.140625
0x06  		256  		122.0703125
0x07 	 	1024  		30.517578125
TCCR2B = TCCR2B & 0b11111000 | <setting>;