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7-2
8XC196NP, 80C196NU USER’S MANUAL
Table 7-3 lists the registers associated with the bidirectional ports. Each port has three control reg-
isters (Px_MODE, Px_DIR, and Px_REG); they can be both read and written. The Px_PIN regis-
ter is a status register that returns the logic level present on the pins; it can only be read. The
registers are byte-addressable and can be windowed.“Bidirectional Port Considerations” on page
7-9 discusses special considerations for reading P2_REG.7.
Table 7-2. Bidirectional Port Pins
Port Pin
Special-function
Signal(s)
Special-function
Signal Type
Associated
Peripheral
P1.0 EPA0 I/O EPA
P1.1 EPA1 I/O EPA
P1.2 EPA2 I/O EPA
P1.3 EPA3 I/O EPA
P1.4 T1CLK I Timer 1
P1.5 T1DIR I Timer 1
P1.6 T2CLK I Timer 2
P1.7 T2DIR I Timer 2
P2.0 TXD O SIO
P2.1 RXD I/O SIO
P2.2 EXTINT0 I Interrupts
P2.3 BREQ# O Bus controller
P2.4 EXTINT1 I Interrupts
P2.5 HOLD# I Bus controller
P2.6 HLDA# O Bus controller
P2.7 CLKOUT O Clock generator
P3.0 CS0# O Chip-select unit
P3.1 CS1# O Chip-select unit
P3.2 CS2# O Chip-select unit
P3.3 CS3# O Chip-select unit
P3.4 CS4# O Chip-select unit
P3.5 CS5# O Chip-select unit
P3.6 EXTINT2 I Interrupts
P3.7 EXTINT3 I Interrupts
P4.0 PWM0 O PWM
P4.1 PWM1 O PWM
P4.2 PWM2 O PWM
P4.3 — I/O —