Freescale Semiconductor, Inc.
Pinout and Signal Descriptions
3.3.8 VSTBY
Stand-by voltage supply to static RAM. Used to maintain the contents of
RAM with minimal power when the rest of the chip is powered down.
Table 3-1. Power and Ground Connection Summary
Pin Number
Mnemonic
Description
112-pin QFP
VDD
VSS
12, 65
14, 66
42, 107
40, 106
85
Internal power and ground.
VDDX
VSSX
VDDA
VSSA
VRH1
VRL1
External power and ground, supply to pin drivers.
Operating voltage and ground for the analog-to-digital converter, allows the
supply voltage to the A/D to be bypassed independently.
88
86
Reference voltages for the analog-to-digital converter 1
Reference voltages for the analog-to-digital converter 0.
87
VRH0
VRL0
67
68
VDDPLL
VSSPLL
43
Provides operating voltage and ground for the Phase-Locked Loop. This allows
the supply voltage to the PLL to be bypassed independently.
45
Program/erase voltage for the Flash EEPROM and required supply for normal
operation.
VFP
97
41
Stand-by voltage supply to maintain the contents of RAM with minimal power
when the rest of the chip is powered down.
VSTBY
3.4 Signal Descriptions
3.4.1 Crystal Driver and External Clock Input (XTAL, EXTAL)
These pins provide the interface for either a crystal or a CMOS
compatible clock to control the internal clock generator circuitry. Out of
reset the frequency applied to EXTAL is twice the desired E–clock rate.
All the device clocks are derived from the EXTAL input frequency.
NOTE: CRYSTAL CIRCUIT IS CHANGED FROM STANDARD.
Technical Data
MC68HC912DG128 — Rev 3.0
Pinout and Signal Descriptions
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