ST72521 STMICROELECTRONICS [STMicroelectronics], ST72521 Datasheet - Page 51

• Manufacturer Part Number: ST72521
• Description: 8-BIT MCU WITH NESTED INTERRUPTS, FLASH, 10-BIT ADC, FIVE TIMERS, SPI, SCI, I2C, CAN INTERFACE
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

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, PE7:34,
PE1:0, PF7:3, PG7:0, PH7:0
Interrupt Ports
PA2:0, PB6:5, PB4, PB2:0, PF1:0 (with pull-up)
Table 11. Port Configuration
* Note: when the CANTX alternate function is selected the I/O port operates in output push-pull mode.
floating input
pull-up input
open drain output
push-pull output
floating input
pull-up interrupt input
open drain output
push-pull output
Port A
Port B
Port C
Port D
Port E
Port G
Port H
Port F
Port
MODE
MODE
PA7:6
PA5:4
PA3
PA2:0
PB7, PB3
PB6:5, PB4,
PB2:0
PC7:0
PD7:0
PE7:3, PE1:0
PE2
PF7:3
PF2
PF1:0
PG7:0
PH7:0
Pin name
DDR
DDR
0
0
1
1
0
0
1
1
OR = 0
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
floating
OR
OR
0
1
0
1
0
1
0
1
floating
Input
floating interrupt
floating interrupt
floating interrupt
pull-up interrupt
pull-up interrupt
pull-up interrupt
PA3, PB7, PB3, PF2 (without pull-up)
True Open Drain Ports
PA7:6
Pull-up Input Port (CANTX requirement)
PE2
OR = 1
floating input
floating interrupt input
open drain output
push-pull output
floating input
open drain (high sink ports)
pull-up
pull-up
pull-up
pull-up
pull-up
pull-up
pull-up
pull-up input only *
MODE
MODE
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
open drain
OR = 0
pull-up input
MODE
true open-drain
Output
DDR
0
0
1
1
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
push-pull
OR = 1
ST72521
DDR
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OR
0
1
0
1
0
1