mc68hc912d60c Freescale Semiconductor, Inc, mc68hc912d60c Datasheet - Page 444

• Manufacturer Part Number: mc68hc912d60c
• Description: Hc12 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

Appendix: Information on MC68HC912D60A Mask
23.4 Clock Circuitry
23.5 Pseudo Stop Mode
23.6 Oscillator
Technical Data
444
NOTE:
Appendix: Information on MC68HC912D60A Mask Set Changes Freescale Semiconduc-
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.
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.
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.
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.
MC68HC912D60A — Rev. 3.1