fix for adafruit#49

Author: ladyada

variants/itsybitsy_m4/variant.cpp

@@ -36,7 +36,7 @@ const PinDescription g_APinDescription[]=
   { PORTA,  14, PIO_DIGITAL, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM1_CH2, TCC1_CH2, EXTERNAL_INT_14 }, // D4
   { PORTA,  15, PIO_DIGITAL, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER), No_ADC_Channel, PWM1_CH3, TCC1_CH3, EXTERNAL_INT_15 }, // D5
   { PORTB,   2, PIO_ANALOG, PIN_ATTR_ANALOG, ADC_Channel14, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_2 }, // Dotstar Clock (D6)
-  { PORTA,  19, PIO_TIMER_ALT, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER_ALT), No_ADC_Channel, PWM1_CH3, TCC1_CH3, EXTERNAL_INT_3 }, // D7
+  { PORTA,  18, PIO_TIMER_ALT, (PIN_ATTR_DIGITAL|PIN_ATTR_PWM|PIN_ATTR_TIMER_ALT), No_ADC_Channel, PWM1_CH2, TCC1_CH2, EXTERNAL_INT_2 }, // D7
 
   // Digital High
   { PORTB,   3, PIO_ANALOG, PIN_ATTR_ANALOG, ADC_Channel15, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_3 }, // Dotstar Data (D8)