S12SCIV2SLASHD datasheet(90/130 Pages) FREESCALE

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MC9S12H256 Device User Guide — V01.18

VDD1, VSS1 and VSS2 are the supply pins for the digital logic, VDDPLL, VSSPLL supply the oscillator

and the PLL.

VSS1 and VSS2 are internally connected by metal.

VDDA, VDDX1, VDDX2, VDDM as well as VSSA, VSSX1, VSSX2 and VSSM are connected by

anti-parallel diodes for ESD protection.

NOTE:

In the following context VDD5 is used for either VDDA, VDDM, VDDR and

VDDX1/2; VSS5 is used for either VSSA, VSSR and VSSX unless otherwise noted.

IDD5 denotes the sum of the currents flowing into the VDDA, VDDX1/2, VDDM

and VDDR pins.

VDD is used for VDD1 and VDDPLL, VSS is used for VSS1, VSS2 and VSSPLL.

IDD is used for the sum of the currents flowing into VDD1 and VDDPLL.

A.1.3 Pins

There are four groups of functional pins.

A.1.3.1 5V I/O pins

Those I/O pins have a nominal level of 5V. This class of pins is comprised of all port I/O pins, the analog

inputs, BKGD and the RESET pins.The internal structure of all those pins is identical, however some of

the functionality may be disabled. E.g. for the analog inputs the output drivers, pull-up and pull-down

resistors are disabled permanently.

A.1.3.2 Analog Reference

This group is made up by the VRH and VRL pins.

A.1.3.3 Oscillator

The pins XFC, EXTAL, XTAL dedicated to the oscillator have a nominal 2.5V level. They are supplied

by VDDPLL.

A.1.3.4 TEST

This pin is used for production testing only.

A.1.4 Current Injection

Power supply must maintain regulation within operating VDD5 or VDD range during instantaneous and

operating maximum current conditions. If positive injection current (Vin >VDD5) is greater than IDD5, the

injection current may flow out of VDD5 and could result in external power supply going out of regulation.

Ensure external VDD5 load will shunt current greater than maximum injection current. This will be the

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S12SCIV2/D Datasheet(PDF) 90 Page - Freescale Semiconductor, Inc