MC68HC12 Datasheet, PDF (458/478 Pages) Motorola, Inc – The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit

Appendix: Information on MC68HC912DT128A
3. Change to the input ESD resistor from EXTAL to the gate of the
oscillator amplifier to provide a parallel path, reducing parasitic
phase shift in the oscillator.
Additionally a new Pierce ("P") oscillator configurations has been added.
See Section 13. Oscillator for full details.
24.4 Flash Protection Feature
A flash protection bit has been added to the EEMCR register to protect
the Flash memory from accidental program or erasure. This bit is loaded
from the EEPROM Shadow word at reset, so that the flash can be
protected before any software is executed.
See EEPROM and Flash sections for more details.
24.5 Clock Circuitry
The crystal oscillator output is now frozen when Limp Home (LH) mode
is entered to prevent rapid switching between crystal and LH clocks.
Improvements have been made to the bus clock switching circuitry to
eliminate the potential for glitches to appear on the internal clock line.
The duration of the clock monitor pulses was increased to reduce
sensitivity of the clock monitor circuit to short clock pulses.
24.6 Pseudo Stop Mode
Oscillator amplifier drive is now not reduced in Pseudo Stop mode.
When exiting Pseudo Stop mode, the device will now not go into Limp
Home Mode since the crystal is already running.
Technical Data
458
MC68HC912DT128A — Rev 4.0
Appendix: Information on MC68HC912DT128A Mask Set Changes
MOTOROLA