AN2021 datasheet(20/39 Pages) STMICROELECTRONICS

Teilenummer	AN2021

Bauteilbeschribung	The ST10F272B and ST10F272E are members of the STMicroelectronics

PDF	39 Pages

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Hersteller	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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20 / 39 page

Modified features

AN2021

20/39

1.9.1

Hardware impact

Port0 configuration might be changed with regards to the new PLL factor.

All configurations need a crystal (or ceramic resonator) to generate the CPU clock through

the internal oscillator amplifier, except for the Direct Drive mode (oscillator amplifier

disabled, so no crystal or resonator can be used). Vice versa, the clock can be forced

through an external clock source only in Direct Drive mode.

The components on XTAL1 and XTAL2 (crystal and capacitors, or resonator) must be

changed as:

●

the input frequency range is now reduced

●

it is no longer possible to use a crystal or a ceramic resonator in direct drive mode

●

it is no longer possible to use a PLL factor with a frequency generator

●

the electrical characteristics of the main oscillator have changed (transconductance)

1.9.2

Software impact

None.

AN2021 Datenblatt(PDF) 20 Page - STMicroelectronics