RM0016 datasheet(87/467 Pages) STMICROELECTRONICS

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RM0016

Clock control (CLK)

104

9.5

Peripheral clock-gating (PCG)

Gating the clock to unused peripherals helps reduce power consumption. Peripheral clock

Gating (PCG) mode allows you to selectively enable or disable the fMASTER clock

connection to the following peripherals at any time in Run mode:

•

ADC

•

I2C

•

AWU (register clock, not counter clock)

•

SPI

•

TIM[4:1]

•

UART

•

CAN (register clock, not CAN clock)

After a device reset, all peripheral clocks are enabled. You can disable the clock to any

peripheral by clearing the corresponding PCKEN bit in the Peripheral clock gating register 1

(CLK_PCKENR1) and in the Peripheral clock gating register 2 (CLK_PCKENR2). But you

have to disable properly the peripheral using the appropriate bit, before stopping the

corresponding clock.

To enable a peripheral, you must first enable the corresponding PCKEN bit in the

CLK_PCKENR registers and then set the peripheral enable bit in the peripheral’s control

registers.

The AWU counter is driven by an internal or external clock (LSI or HSE) independent from

fMASTER, so that it continues to run even if the register clock to this peripheral is switched

off.

RM0016 Datasheet(PDF) 87 Page - STMicroelectronics