Digital I/O Registers
9-7Digital I/O
9.3 Digital I/O Registers
Seven registers are used to configure P1 and P2. Four registers are used to
configure ports P3 - P6. The digital I/O registers are listed in Table 91.

Table 9−1.Digital I/O Registers

Port Register Short Form Address Register Type Initial State
P1 Input P1IN 020h Read only
Output P1OUT 021h Read/write Unchanged
Direction P1DIR 022h Read/write Reset with PUC
Interrupt Flag P1IFG 023h Read/write Reset with PUC
Interrupt Edge Select P1IES 024h Read/write Unchanged
Interrupt Enable P1IE 025h Read/write Reset with PUC
Port Select P1SEL 026h Read/write Reset with PUC
P2 Input P2IN 028h Read only
Output P2OUT 029h Read/write Unchanged
Direction P2DIR 02Ah Read/write Reset with PUC
Interrupt Flag P2IFG 02Bh Read/write Reset with PUC
Interrupt Edge Select P2IES 02Ch Read/write Unchanged
Interrupt Enable P2IE 02Dh Read/write Reset with PUC
Port Select P2SEL 02Eh Read/write Reset with PUC
P3 Input P3IN 018h Read only
Output P3OUT 019h Read/write Unchanged
Direction P3DIR 01Ah Read/write Reset with PUC
Port Select P3SEL 01Bh Read/write Reset with PUC
P4 Input P4IN 01Ch Read only
Output P4OUT 01Dh Read/write Unchanged
Direction P4DIR 01Eh Read/write Reset with PUC
Port Select P4SEL 01Fh Read/write Reset with PUC
P5 Input P5IN 030h Read only
Output P5OUT 031h Read/write Unchanged
Direction P5DIR 032h Read/write Reset with PUC
Port Select P5SEL 033h Read/write Reset with PUC
P6 Input P6IN 034h Read only
Output P6OUT 035h Read/write Unchanged
Direction P6DIR 036h Read/write Reset with PUC
Port Select P6SEL 037h Read/write Reset with PUC