
Pinout and Signal Descriptions
Power Supply Pins
68HC(9)12D60 — Rev 4.0
Advance Information
MOTOROLA
Pinout and Signal Descriptions
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43
3.4.5 V
DDPLL
, V
SSPLL
Provides operating voltage and ground for the Phased-Locked Loop.
This allows the supply voltage to the PLL to be bypassed independently.
NOTE:
The VSSPLL pin should always be grounded even if the PLL is not used.
The VDDPLL pin should not be left floating. It is recommended to
connect the VDDPLL pin to ground if the PLL is not used.
3.4.6 XFC
PLL loop filter. Please see
Appendix: CGM Practical Aspects
for
information on how to calculate PLL loop filter elements. Any current
leakage on this pin must be avoided.
Figure 3-5. PLL Loop FIlter Connections
If VDDPLL is connected to VSS (this is normal case), then the XFC pin
should either be left floating or connected to VSS (
never
to VDD). If
VDDPLL is tied to VDD but the PLL is switched off (PLLON bit cleared),
then the XFC pin should be connected preferably to VDDPLL (i.e. ready
for VCO minimum frequency).
3.4.7 V
FP
Flash EEPROM programming voltage and supply voltage during normal
operation (68HC912D60 only – on the 68HC12D60 this pin is not
connected and can be tied to 5V or 12V without effect).
MCU
XFC
R
0
C
0
C
p
VDDPLL
F
Freescale Semiconductor, Inc.
n
.