Figure 11. Basic Structure Of A Standard I/O Port Bit; Figure 12. Basic Structure Of A 5-Volt Tolerant I/O Port Bit - ST STM32F100 Series Reference Manual

RM0041
To on-chip
peripheral
Read
Write
Read/write
From on-chip
peripheral
To on-chip
peripheral
Read
Write
Read/write
From on-chip
peripheral
1. V
DD_FT
General-purpose and alternate-function I/Os (GPIOs and AFIOs)

Figure 11. Basic structure of a standard I/O port bit

Analog Input
Alternate Function Input
Alternate Function Output

Figure 12. Basic structure of a 5-Volt tolerant I/O port bit

Analog Input
Alternate Function Input
Alternate Function Output
is a potential specific to 5-Volt tolerant I/Os, and different from V
on/off
TTL Schmitt
trigger
Input driver
Output driver
Output
control
on/off
TTL Schmitt
trigger
Input driver
Output driver
Output
control
RM0041 Rev 6
V
DD
on/off
on/off
V
SS
V
DD
P-MOS
N-MOS
V
SS
Push-pull,
open-drain or
disabled
V
DD
on/off
V
on/off
V
SS
V
DD
P-MOS
N-MOS
V
SS
Push-pull,
open-drain or
disabled
.
DD
V
DD
Protection
diode
I/O pin
Protection
diode
V
SS
ai14781
(1)
DD_FT
I/O pin
Protection
diode
V
SS
ai14782
103/709
131