
Connectivity line devices: reset and clock control (RCC)
RM0008
150/1096
Doc ID 13902 Rev 12
8.3.12 Clock
configuration register2 (RCC_CFGR2)
Address offset: 0x2C
Reset value: 0x0000 0000
Access: no wait state, word, half-word and byte access
7
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
Reserved
I2S3S
RC
I2S2S
RC
PREDI
V1SRC
rw
rw
rw
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
PLL3MUL[3:0]
PLL2MUL[3:0]
PREDIV2[3:0]
PREDIV1[3:0]
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
rw
Bits 31:19 Reserved, always read as 0.
Bit 18
I2S3SRC
: I2S3 clock source
Set and cleared by software to select I2S3 clock source. This bit must be valid before
enabling I2S3 clock.
0: System clock (SYSCLK) selected as I2S3 clock entry
1: PLL3 VCO clock selected as I2S3 clock entry
Bit 17
I2S2SRC
: I2S2 clock source
Set and cleared by software to select I2S2 clock source. This bit must be valid before
enabling I2S2 clock.
0: System clock (SYSCLK) selected as I2S2 clock entry
1: PLL3 VCO clock selected as I2S2 clock entry
Bit 16
PREDIV1SRC
: PREDIV1 entry clock source
Set and cleared by software to select PREDIV1 clock source. This bit can be written only
when PLL is disabled.
0: HSE oscillator clock selected as PREDIV1 clock entry
1: PLL2 selected as PREDIV1 clock entry
Bits 15:12
PLL3MUL[3:0]
: PLL3 Multiplication Factor
Set and cleared by software to control PLL3 multiplication factor. These bits can be written
only when PLL3 is disabled.
00xx: Reserved
010x: Reserved
0110: PLL3 clock entry x 8
0111: PLL3 clock entry x 9
1000: PLL3 clock entry x 10
1001: PLL3 clock entry x 11
1010: PLL3 clock entry x 12
1011: PLL3 clock entry x 13
1100: PLL3 clock entry x 14
1101: Reserved
1110: PLL3 clock entry x 16
1111: PLL3 clock entry x 20