HCS12 datasheet(84/126 Pages) NXP

84 / 126 page

Device User Guide — 9S12KT256DGV1/D V01.09

Freescale Semiconductor

The VDDR, VSSR pair supplies the internal voltage regulator.

VDD1, VSS1, VDD2 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.

VDD1 and VDD2 are internally connected by metal.

VDDA, VDDX, VDDR as well as VSSA, VSSX, VSSR are connected by anti-parallel diodes for ESD

protection.

NOTE:

In the following context VDD5 is used for either VDDA, VDDR and VDDX; VSS5

is used for either VSSA, VSSR and VSSX unless otherwise noted. IDD5 denotes the

sum of the currents flowing into the VDDA, VDDX and VDDR pins. VDD is used

for VDD1, VDD2 and VDDPLL, VSS is used for VSS1, VSS2 and VSSPLL. IDD is

used for the sum of the currents flowing into VDD1 and VDD2.

A.1.3 Pins

There are four groups of functional pins.

A.1.3.1 3.3V/5V I/O pins

Those I/O pins have a nominal level of 3.3V or 5V depending on the application operating point. This

group of pins is comprised of all port I/O pins, the analog inputs, BKGD pin and the RESET inputs.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 of pins is comprised of the VRH and VRL pins.

A.1.3.3 Oscillator

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

VDDPLL.

A.1.3.4 PLL

The pin XFC dedicated to the oscillator have a nominal 2.5V level. It is supplied by VDDPLL.

A.1.3.5 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.

HCS12 Datasheet(PDF) 84 Page - NXP Semiconductors