IO_IER register
| PA0_IE | PA0_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA1_IE | PA1_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA2_IE | PA2_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA3_IE | PA3_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA4_IE | PA4_IE: Interrupt enable for port A I/Os. | 
| PA5_IE | PA5_IE: Interrupt enable for port A I/Os. | 
| PA6_IE | PA6_IE: Interrupt enable for port A I/Os. | 
| PA7_IE | PA7_IE: Interrupt enable for port A I/Os. | 
| PA8_IE | PA8_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA9_IE | PA9_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA10_IE | PA10_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA11_IE | PA11_IE: Interrupt enable for port A I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PA12_IE | PA12_IE: Interrupt enable for port A I/Os. | 
| PA13_IE | PA13_IE: Interrupt enable for port A I/Os. | 
| PA14_IE | PA14_IE: Interrupt enable for port A I/Os. | 
| PA15_IE | PA15_IE: Interrupt enable for port A I/Os. | 
| PB0_IE | PB0_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB1_IE | PB1_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB2_IE | PB2_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB3_IE | PB3_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB4_IE | PB4_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB5_IE | PB5_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB6_IE | PB6_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB7_IE | PB7_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB8_IE | PB8_IE: Interrupt enable for port B I/Os. | 
| PB9_IE | PB9_IE: Interrupt enable for port B I/Os. | 
| PB10_IE | PB10_IE: Interrupt enable for port B I/Os. | 
| PB11_IE | PB11_IE: Interrupt enable for port B I/Os. | 
| PB12_IE | PB12_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB13_IE | PB13_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB14_IE | PB14_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. | 
| PB15_IE | PB15_IE: Interrupt enable for port B I/Os. 0: interrupt is disabled. 1: interrupt is enabled. |