MC912D60AVPVE8 Datasheet, PDF (444/460 Pages) Freescale Semiconductor, Inc – HC12 Microcontrollers

Appendix: Information on MC68HC912D60A Mask
23.4 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.
23.5 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.
23.6 Oscillator
The Automatic Level Control (ALC) capacitor reference was changed
from VDD to VSS in the crystal oscillator circuit to improve noise
immunity.
Parasitic capacitance on internal signal lines has been decreased, thus
decreasing sensitivity to external capacitance changes.
NOTE: For best oscillator performance, it is recommended that the load
capacitor selection is verified on changing to the 1L02H mask.
A reduction was made to the gain of the Operational Transconductance
Amplifier (OTA) to reduce the amplification of any noise on the EXTAL
pin. This is a small incremental improvement.
Technical Data
444
MC68HC912D60A — Rev. 3.1
Appendix: Information on MC68HC912D60A Mask Set Changes Freescale Semiconduc-