MC9S12HZ256 Datasheet, PDF (37/692 Pages) Freescale Semiconductor, Inc – HCS12 Microcontrollers

Chapter 1 MC9S12HZ256 Device Overview
Mnemonic
V_LCD
V_DD1
V_SS1
V_SS2
V_DDR
V_SSR
V_DDX1
V_DDX2
V_SSX1
V_SSX2
V_DDA
V_SSA
V_RH
V_RL
V_DDPLL
V_SSPLL
V_DDM1,2,3
V_SSM1,2,3
Table 1-9. Power and Ground
Nominal
Voltage
5.0 V
2.5 V
0V
Description
Voltage reference pin for the LCD driver.
Internal power and ground generated by internal regulator. These also allow an external source
to supply the core V_DD/V_SS voltages and bypass the internal voltage regulator.
5.0 V
0V
5.0 V
External power and ground, supply to pin drivers and internal voltage regulator.
External power and ground, supply to pin drivers.
0V
5.0 V
0V
5.0 V
0V
2.5 V
0V
5.0 V
0V
Operating voltage and ground for the analog-to-digital converter and the reference for the internal
voltage regulator, allows the supply voltage to the A/D to be bypassed independently.
Reference voltage high for the ATD converter.
Reference voltage low for the ATD converter.
Provides operating voltage and ground for the phased-locked Loop. This allows the supply
voltage to the PLL to be bypassed independently. Internal power and ground generated by
internal regulator.
Provides operating voltage and ground for motor 0, 1, 2 and 3.
NOTE
All V_SS pins must be connected together in the application. Because fast
signal transitions place high, short-duration current demands on the power
supply, use bypass capacitors with high-frequency characteristics and place
them as close to the MCU as possible. Bypass requirements depend on
MCU pin load.
1.5 Detailed Signal Descriptions
1.5.1 EXTAL, XTAL — Oscillator Pins
EXTAL and XTAL are the crystal driver and external clock pins. On reset all the device clocks are derived
from the EXTAL input frequency. XTAL is the crystal output.
1.5.2 RESET — External Reset Pin
An active low bidirectional control signal, it acts as an input to initialize the MCU to a known start-up
state, and an output when an internal MCU function causes a reset.
MC9S12HZ256 Data Sheet, Rev. 2.04
Freescale Semiconductor
37