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Digital I/O Registers
9-7
Digital 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 9−1.
Table 9−1.Digital I/O Registers
Port Register Short Form Address Register Type Initial State
P1
Input
P1IN 020h Read only −
P1
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 −
P2
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 −
P3
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 −
P4
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 −
P5
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 −
P6
Output
P6OUT 035h Read/write Unchanged
Direction
P6DIR 036h Read/write Reset with PUC
Port Select
P6SEL 037h Read/write Reset with PUC