Datasheet

ST72321Rx ST72321ARx ST72321Jx
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I/O PORTS (Cont’d)
9.5.1 I/O Port Implementation
The I/O port register configurations are summa-
rised as follows.
Standard Ports
PA5:4, PC7:0, PD7:0, PE7:3,
PE1:0, PF7:3,
Interrupt Ports
PA2:0, PB6:5, PB4, PB2:0, PF1:0 (with pull-up)
PA3, PB7, PB3, PF2 (without pull-up)
True Open Drain Ports
PA7:6
Pull-Up Input Port PE2
Table 12. Port Configuration
MODE DDR OR
floating input 0 0
pull-up input 0 1
open drain output 1 0
push-pull output 1 1
MODE DDR OR
floating input 0 0
pull-up interrupt input 0 1
open drain output 1 0
push-pull output 1 1
MODE DDR OR
floating input 0 0
floating interrupt input 0 1
open drain output 1 0
push-pull output 1 1
MODE DDR
floating input 0
open drain (high sink ports) 1
MODE
pull-up input
Port Pin name
Input Output
OR = 0 OR = 1 OR = 0 OR = 1
Port A
PA7:6 floating true open-drain
PA5:4 floating pull-up open drain push-pull
PA3 floating floating interrupt open drain push-pull
PA2:0 floating pull-up interrupt open drain push-pull
Port B
PB7, PB3 floating floating interrupt open drain push-pull
PB6:5, PB4,
PB2:0
floating pull-up interrupt open drain push-pull
Port C PC7:0 floating pull-up open drain push-pull
Port D PD7:0 floating pull-up open drain push-pull
Port E
PE7:3, PE1:0 floating pull-up open drain push-pull
PE2 (Flash de-
vices)
pull-up input only
PE2 (ROM de-
vices)
floating floating open drain push-pull
Port F
PF7:3 floating pull-up open drain push-pull
PF2 floating floating interrupt open drain push-pull
PF1:0 floating pull-up interrupt open drain push-pull