mc9s12e256 Freescale Semiconductor, Inc, mc9s12e256 Datasheet - Page 167

• Manufacturer Part Number: mc9s12e256
• Description: Hcs12 Microcontrollers 16-bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

4.2
This section lists and describes the signals that connect off chip.
4.2.1
These pins provides operating voltage (V
the supply voltage to the PLL to be independently bypassed. Even if PLL usage is not required V
and V
4.2.2
A passive external loop filter must be placed on the XFC pin. The filter is a second-order, low-pass filter
to eliminate the VCO input ripple. The value of the external filter network and the reference frequency
determines the speed of the corrections and the stability of the PLL. Refer to
Device Overview (MC9S12E256DGV1)”
usage is not required the XFC pin must be tied to V
Freescale Semiconductor
1
Refer to the device overview section for availability of the low-voltage reset feature.
SSPLL
XCLKS
EXTAL
XTAL
External Signal Description
RESET
V
V
V
XFC — PLL Loop Filter Pin
must be connected properly.
XFC
DDPLL
SSPLL
DDPLL
Regulator
Monitor
Oscil-
Voltage
Clock
lator
, V
SSPLL
OSCCLK
PLL
CRG
— PLL Operating Voltage, PLL Ground
Power-on Reset
Low Voltage Reset
PLLCLK
Figure 4-1. CRG Block Diagram
MC9S12E256 Data Sheet, Rev. 1.08
CM fail
DDPLL
for calculation of PLL loop filter (XFC) components. If PLL
) and ground (V
Clock and Reset
1
DDPLL
Clock Quality
COP
Registers
Control
Generator
Checker
Reset
.
SSPLL
RTI
Chapter 4 Clocks and Reset Generator (CRGV4)
) for the PLL circuitry. This allows
Chapter 1, “MC9S12E256
Real-Time Interrupt
PLL Lock Interrupt
Self-Clock Mode
Oscillator Clock
System Reset
Core Clock
Bus Clock
Interrupt
DDPLL
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