RM0401 Rev 3 131/771
RM0401 Reset and clock control (RCC)
134
5.3.17 RCC Dedicated Clocks Configuration Register (RCC_DCKCFGR)
Address offset: 0x8C
Reset value: 0x0000 0000
Access: no wait state, word, half-word and byte access.
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
Res. Res. Res. Res. Res. I2SSCR TIMPRE Res. Res. Res. Res. Res. Res. Res. Res.
rw rw rw
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res. Res.
Bits 31:27 Reserved, must be kept at reset value.
Bits 26:25 I2SSRC: I2S APB clock source selection
Set and reset by software to configure the frequency of the I2S clock. These bits must be
written when the PLL is disabled.
00: I2S clock frequency = f
PPLCLK_R
01: I2S clock frequency = Alternate function input frequency
1x: I2S clock frequency = HSI/HSE depending on PLLRC (bit 22 of RCC_PLLCFGR
register)
Bit 24 TIMPRE: Timers clocks prescalers selection
Set and reset by software to control the clock frequency of all the timers connected to APB1
and APB2 domain.
0: If the APB prescaler (PPRE1, PPRE2 in the RCC_CFGR register) is configured to a
division factor of 1, TIMxCLK = HCKL. Otherwise, the timer clock frequencies are set to
twice to the frequency of the APB domain to which the timers are connected:
TIMxCLK = 2xPCLKx.
1:If the APB prescaler (PPRE1, PPRE2 in the RCC_CFGR register) is configured to a
division factor of 1 or 2, TIMxCLK = HCKL. Otherwise, the timer clock frequencies are set to
four times to the frequency of the APB domain to which the timers are connected:
TIMxCLK = 4xPCLKx.
Bits 23: 0 Reserved, must be kept at reset value.