STM8AF6213 Datasheet, PDF(16/106 Page) STMicroelectronics – Automotive 8-bit MCU, with up to 8 Kbyte Flash, data EEPROM, 10-bit ADC, timers, LIN, SPI, IC, 3 to 5.5 V

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STM8AF6213 Datasheet, PDF (16/106 Pages) STMicroelectronics – Automotive 8-bit MCU, with up to 8 Kbyte Flash, data EEPROM, 10-bit ADC, timers, LIN, SPI, IC, 3 to 5.5 V

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Product overview

STM8AF6213/23/23A/26

4.5

4.5.1

Clock controller

The clock controller distributes the system clock (fMASTER) coming from different oscillators

to the core and the peripherals. It also manages clock gating for low-power modes and

ensures clock robustness.

Features

ï· Clock prescaler: to get the best compromise between speed and current consumption

the clock frequency to the CPU and peripherals can be adjusted by a programmable

prescaler.

ï· Safe clock switching: Clock sources can be changed safely on the fly in Run mode

through a configuration register. The clock signal is not switched until the new clock

source is ready. The design guarantees glitch-free switching.

ï· Clock management: To reduce power consumption, the clock controller can stop the

clock to the core, individual peripherals or memory.

ï· Master clock sources: four different clock sources can be used to drive the master

clock:

â 1-16 MHz high-speed external crystal (HSE)

â Up to 16 MHz high-speed user-external clock (HSE user-ext)

â 16 MHz high-speed internal RC oscillator (HSI)

â 128 kHz low-speed internal RC (LSI)

ï· Startup clock: after reset, the microcontroller restarts by default with an internal 2 MHz

clock (HSI/8). The prescaler ratio and clock source can be changed by the application

program as soon as the code execution starts.

ï· Clock security system (CSS): this feature can be enabled by software. If an HSE

clock failure occurs, the internal RC (16 MHz/8) is automatically selected by the CSS

and an interrupt can optionally be generated.

ï· Configurable main clock output (CCO): This outputs an external clock for use by the

application.

Table 2. Peripheral clock gating bit assignments in CLK_PCKENR1/2 registers

Bit

Periphera

l clock

Bit

Peripheral

clock

Bit

Peripheral

clock

Bit

Peripheral

clock

PCKEN17

PCKEN16

PCKEN15

PCKEN14

TIM1

TIM5

Reserved

TIM6

PCKEN13

PCKEN12

PCKEN11

PCKEN10

LINUART

Reserved

SPI

I2C

PCKEN27

PCKEN26

PCKEN25

PCKEN24

Reserved

PCKEN23

PCKEN22

PCKEN21

PCKEN20

ADC

AWU

Reserved

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DocID025118 Rev 5

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