ST STM32L4+ Series Reference Manual page 268

Reset and clock control (RCC)
Bit 20 PLLSAI1QEN: PLLSAI1 PLL48M2CLK output enable
Bits 19:18 Reserved, must be kept at reset value.
Bit 17 PLLSAI1P: PLLSAI1 division factor for PLLSAI1CLK (SAI1 or SAI2 clock).
Bit 16 PLLSAI1PEN: PLLSAI1 PLLSAI1CLK output enable
Bit 15 Reserved, must be kept at reset value.
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Set and reset by software to enable the PLL48M2CLK output of the PLLSAI1.
In order to save power, when the PLL48M2CLK output of the PLLSAI1 is not used, the value
of PLLSAI1QEN should be 0.
0: PLL48M2CLK output disable
1: PLL48M2CLK output enable
Set and cleared by software to control the frequency of the PLLSAI1 output clock
PLLSAI1CLK. This output can be selected for SAI1 or SAI2. These bits can be written only if
PLLSAI1 is disabled.
When the PLLSAI1PDIV[4:0] is set to "00000",PLLSAI1CLK output clock frequency =
VCOSAI1 frequency / PLLSAI1P with PLLSAI1P =7, or 17
0: PLLSAI1P = 7
1: PLLSAI1P = 17
Set and reset by software to enable the PLLSAI1CLK output of the PLLSAI1.
In order to save power, when the PLLSAI1CLK output of the PLLSAI1 is not used, the value
of PLLSAI1PEN should be 0.
0: PLLSAI1CLK output disable
1: PLLSAI1CLK output enable
RM0432 Rev 6
RM0432