Merge pull request #110 from sparkfun/SAMD51_Thing_Plus_External_Interrupt_7

Gives external interrupt capabilities to "D9"

Author: edspark

sparkfun/samd/variants/SparkFun_SAMD51_Thing_Plus/variant.cpp

@@ -47,7 +47,7 @@ const PinDescription g_APinDescription[]=
   { NOT_A_PORT, 0,  PIO_NOT_A_PIN, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
   { NOT_A_PORT, 0,  PIO_NOT_A_PIN, PIN_ATTR_NONE, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE },
 
-  { PORTA,  7,  PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_NONE }, //pin 9
+  { PORTA,  7,  PIO_DIGITAL, PIN_ATTR_DIGITAL, No_ADC_Channel, NOT_ON_PWM, NOT_ON_TIMER, EXTERNAL_INT_7 }, //pin 9
   { PORTA,  18, PIO_TIMER_ALT, PIN_ATTR_PWM_F, No_ADC_Channel, TCC1_CH2, TC3_CH0, EXTERNAL_INT_2 },
   { PORTA,  16, PIO_TIMER_ALT, PIN_ATTR_PWM_G, No_ADC_Channel, TCC1_CH0, NOT_ON_TIMER, EXTERNAL_INT_0 },
   { PORTA,  19, PIO_TIMER_ALT, PIN_ATTR_PWM_F, No_ADC_Channel, TCC1_CH3, TC3_CH1, EXTERNAL_INT_3 },