
General-purpose I/Os (GPIO)
RM0453
394/1454
RM0453 Rev 2
Figure 44. Basic structure of a 5V-tolerant I/O port bit
Alternate function output
Alternate function input
Push-pull,
open-drain or
disabled
Out
p
ut
data
re
giste
r
Read/write
From on-chip
peripheral
To on-chip
peripheral
Output
control
on/off
Pull
Pull
on/off
I/O pin
V
DDIOx
V
DDIOx
V
SS
V
SS
TTL Schmitt
trigger
V
SS
VDD_FT
(1)
Protection
diode
Protection
diode
on/off
Input driver
Output driver
down
up
P-MOS
N-MOS
Read
Bit set/
reset
regist
ers
Write
Input
data
re
gist
er
ai15939e
1) VDD_FT is specific to 5V-tolerant I/Os and different from VDD.
Table 70. Port bit configurations
MODE(i)[1:0]
OTYPER(i)
OSPEED(i)[1:0]
PUPD(i)[1:0]
I/O configuration
(1)
01
0
SPEED[1:0]
00
GP output
PP
0
01
GP output
PP + PU
0
10
GP output
PP + PD
0
11
Reserved
1
00
GP output
OD
1
01
GP output
OD + PU
1
10
GP output
OD + PD
1
11
Reserved (GP output OD)
10
0
00
AF
PP
0
01
AF
PP + PU
0
10
AF
PP + PD
0
11
Reserved
1
00
AF
OD
1
01
AF
OD + PU
1
10
AF
OD + PD
1
11
Reserved