mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 114

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

5.3.2 Clock Synthesizer Operation
5-6
MOTOROLA
*
*
RESISTANCE AND CAPACITANCE BASED ON A TEST CIRCUIT CONSTRUCTED WITH A DAISHINKU DMX-38 32.768-KHZ CRYSTAL.
SPECIFIC COMPONENTS MUST BE BASED ON CRYSTAL TYPE. CONTACT CRYSTAL VENDOR FOR EXACT CIRCUIT.
RESISTANCE AND CAPACITANCE BASED ON A TEST CIRCUIT CONSTRUCTED WITH A KDS041-18 4.194 MHz CRYSTAL.
SPECIFIC COMPONENTS MUST BE BASED ON CRYSTAL TYPE. CONTACT CRYSTAL VENDOR FOR EXACT CIRCUIT.
A 4.194 MHz crystal is typically used for a fast reference, but the frequency may vary
between 1 MHz to 6 MHz. Figure 5-4 shows a typical circuit.
If a fast or slow reference frequency is provided to the PLL from a source other than a
crystal, or an external system clock signal is applied through the EXTAL pin, the XTAL
pin must be left floating.
either a crystal or an externally supplied reference frequency. A separate power
source increases MCU noise immunity and can be used to run the clock when the
MCU is powered down. A quiet power supply must be used as the V
equate external bypass capacitors should be placed as close as possible to the
V
signal is applied and the PLL is disabled, V
supply.
V
DDSYN
DDSYN
pin to assure a stable operating frequency. When an external system clock
is used to power the clock circuits when the system clock is synthesized from
Figure 5-3 Slow Reference Crystal Circuit
Figure 5-4 Fast Reference Crystal Circuit
Freescale Semiconductor, Inc.
For More Information On This Product,
V
C1
27 PF*
C2
27 PF*
V
C1
22 pF*
C2
22 pF*
SSI
SSI
Go to: www.freescale.com
R1
330K
R1
1.5K
R2
10M
R2
1M
DDSYN
should be connected to the V
EXTAL
EXTAL
XTAL
XTAL
DDSYN
MC68HC16Y3/916Y3
USER’S MANUAL
source. Ad-
16 OSCILLATOR 4M
32 OSCILLATOR
DD