Datasheet

Pinout and Signal Descriptions
Signal Descriptions
MC68HC912DT128A — Rev 4.0 Technical Data
MOTOROLA Pinout and Signal Descriptions 47
3.3.7 V
STBY
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.
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.
3.4.1.1 Crystal Connections
Refer to Section 13. Oscillator for details of crystal connections.
Table 3-1. MC68HC912DT128A Power and Ground Connection Summary
Mnemonic
Pin Number
Description
112-pin QFP
V
DD
12, 65
Internal power and ground.
V
SS
14, 66
V
DDX
42, 107
External power and ground, supply to pin drivers.
V
SSX
40, 106
V
DDA
85
Operating voltage and ground for the analog-to-digital converter, allows the
supply voltage to the A/D to be bypassed independently.
V
SSA
88
V
RH1
86
Reference voltages for the analog-to-digital converter 1
V
RL1
87
V
RH0
67
Reference voltages for the analog-to-digital converter 0.
V
RL0
68
V
DDPLL
43
Provides operating voltage and ground for the Phase-Locked Loop. This allows
the supply voltage to the PLL to be bypassed independently.
V
SSPLL
45
V
STBY
41
Stand-by voltage supply to maintain the contents of RAM with minimal power
when the rest of the chip is powered down.
Frees
cale Semiconductor,
I
Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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