Figure 9. Basic Structure Of A Standard I/O Port Bit; Figure 10. Basic Structure Of A Five-Volt Tolerant I/O Port Bit - ST STM32F101 Series Reference Manual

General-purpose and alternate-function I/Os (GPIOs and AFIOs)
Figure 9.
To on-chip
peripheral
Read
Write
Read/write
From on-chip
peripheral

Figure 10. Basic structure of a five-volt tolerant I/O port bit

To on-chip
peripheral
Read
Write
Read/write
From on-chip
peripheral
1. V
DD_FT
76/501
Basic structure of a standard I/O port bit
Analog Input
Alternate Function Input
Alternate Function Output
Analog Input
Alternate Function Input
Alternate Function Output
is a potential specific to five-volt tolerant I/Os and different from V
on/off
TTL Schmitt
trigger
Input driver
Output driver
V
Output
control
V
SS
on/off
TTL Schmitt
trigger
Input driver
Output driver
V
Output
control
V
SS
V
DD
on/off
V
DD
on/off
V
SS
DD
P-MOS
V
SS
N-MOS
Push-pull,
open-drain or
disabled
V
DD
on/off
V
DD_FT
on/off
V
SS
DD
P-MOS
V
SS
N-MOS
Push-pull,
open-drain or
disabled
.
DD
RM0008
Protection
diode
I/O pin
Protection
diode
ai14781
(1)
I/O pin
Protection
diode
ai14782