STMicroelectronics STM32WL5 Series Reference Manual page 414

General-purpose I/Os (GPIO)
10.4.9 GPIOx alternate function low register (GPIOx_AFRL) (x = A to B)
Address offset: Block A: 0x0020
Address offset: Block B: 0x0420
Reset value: 0x0000 0000
31 30 29
AFSEL7[3:0]
rw rw rw
15 14 13
AFSEL3[3:0]
rw rw rw
Bits 31:0 AFSELy[3:0]: Port Pxy alternate function selection (y = 7 to 0)
These bits are written by software to configure alternate function I/Os
0x0: AF0 selected
0x1: AF1 selected
0x2: AF2 selected
...
0xE: AF14 selected
0xF: AF15 selected
10.4.10 GPIOx alternate function high register (GPIOx_AFRH) (x = A to B)
Address offset: Block A: 0x0024
Address offset: Block B: 0x0424
Reset value: 0x0000 0000
31 30 29
AFSEL15[3:0]
rw rw rw
15 14 13
AFSEL11[3:0]
rw rw rw
Bits 31:0 AFSELy[3:0]: Port Pxy alternate function selection (y = 15 to 8)
These bits are written by software to configure alternate function I/Os
0x0: AF0 selected
0x1: AF1 selected
0x2: AF2 selected
...
0xE: AF14 selected
0xF: AF15 selected
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28 27 26 25
AFSEL6[3:0]
rw rw rw rw
12 11 10 9
AFSEL2[3:0]
rw rw rw rw
28 27 26 25
AFSEL14[3:0]
rw rw rw rw
12 11 10 9
AFSEL10[3:0]
rw rw rw rw
24 23 22
AFSEL5[3:0]
rw rw rw
8 7 6
AFSEL1[3:0]
rw rw rw
24 23 22
AFSEL13[3:0]
rw rw rw
8 7 6
AFSEL9[3:0]
rw rw rw
RM0453 Rev 5
21 20 19 18
AFSEL4[3:0]
rw rw rw rw
5 4 3 2
AFSEL0[3:0]
rw rw rw rw
21 20 19 18
AFSEL12[3:0]
rw rw rw rw
5 4 3 2
AFSEL8[3:0]
rw rw rw rw
RM0453
17 16
rw rw
1 0
rw rw
17 16
rw rw
1 0
rw rw