ST STM32L4+ Series Reference Manual page 347

RM0432
Bits 31:0 AFSEL[7:0][3:0]: Alternate function selection for port x I/O pin y (y = 7 to 0)
8.4.10 GPIO alternate function high register (GPIOx_AFRH)
(x = A to I)
Address offset: 0x24
Reset value: 0x0000 0000
31 30 29
AFSEL15[3:0]
rw rw rw
15 14 13
AFSEL11[3:0]
rw rw rw
These bits are written by software to configure alternate function I/Os.
0000: AF0
0001: AF1
0010: AF2
0011: AF3
0100: AF4
0101: AF5
0110: AF6
0111: AF7
1000: AF8
1001: AF9
1010: AF10
1011: AF11
1100: AF12
1101: AF13
1110: AF14
1111: AF15
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
AFSEL13[3:0]
rw rw rw
8 7 6
AFSEL9[3:0]
rw rw rw
RM0432 Rev 6
General-purpose I/Os (GPIO)
21 20 19 18
AFSEL12[3:0]
rw rw rw rw
5 4 3 2
AFSEL8[3:0]
rw rw rw rw
17 16
rw rw
1 0
rw rw
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