AN2549 datasheet(15/33 Pages) STMICROELECTRONICS

Part #	AN2549

Description	Porting an application from the ST10F269Zx to the ST10F272Z2

PDF	33 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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15 / 33 page

AN2549

Modified features

15/33

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.

AN2549 Datasheet(PDF) 15 Page - STMicroelectronics