ST7FOXK2 datasheet(37/226 Pages) STMICROELECTRONICS

Teilenummer	ST7FOXK2

Bauteilbeschribung	8-bit MCU with single voltage Flash memory, SPI, I²C, ADC, timers

PDF	226 Pages

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Hersteller	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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37 / 226 page

ST7FOXF1, ST7FOXK1, ST7FOXK2

Supply, reset and clock management

37/226

Case 2 Switching from AWU RC to internal RC

Reset the RC/AWU bit to enable the internal RC oscillator

Using a 4-bit counter, wait until 8 internal RC cycles have elapsed. The counter is

running on internal RC clock.

Wait till the AWU_FLAG is cleared (1AWU RC cycle) and the RC_FLAG is set (2 RC

cycles)

The switch to the internal RC clock is made at the positive edge of the internal RC clock

signal

Once the switch is made, the AWU RC is stopped

Note:

When the internal RC is not selected, it is stopped so as to save power consumption.

When the internal RC is selected, the AWU RC is turned on by hardware when entering

Auto wakeup from Halt mode.

When the external clock is selected, the AWU RC oscillator is always on.

Figure 11.

Clock switching

Internal RC

AWU RC

Set RC/AWU

Poll AWU_FLAG until set

Internal RC

Reset RC/AWU

Poll RC_FLAG until set

AWU RC

ST7FOXK2 Datenblatt(PDF) 37 Page - STMicroelectronics