Using A Ceramic Resonator Instead Of A Crystal Oscillator; Providing An External Clock Source - Intel 8XC196NT User Manual

12.4.2 Using a Ceramic Resonator Instead of a Crystal Oscillator

In cost-sensitive applications, you may choose to use a ceramic resonator instead of a crystal os-
cillator. Ceramic resonators may require slightly different load capacitor values and circuit con-
figurations. Consult the manufacturer's datasheet for the requirements.

12.4.3 Providing an External Clock Source

To use an external clock source, apply a clock signal to XTAL1 and let XTAL2 float (Figure
12-5). To ensure proper operation, the external clock source must meet the minimum high and
low times (T and T
XHXX
(Figure 12-6). The longer the rise and fall times, the higher the probability that external noise will
affect the clock generator circuitry and cause unreliable operation. See the datasheet for required
XTAL1 voltage drive levels and actual specifications.
C1 C1
C2 C2
Note: Note:
Mount oscillator components close to the device and use Mount oscillator components close to the device and use
short, direct traces to XTAL1, XTAL2, and V ss . When short, direct traces to XTAL1, XTAL2, and V ss . When
using crystals, C1=C2≈20 pF. When using ceramic using crystals, C1=C2≈20 pF. When using ceramic
resonators, consult the manufacturer for recommended resonators, consult the manufacturer for recommended
oscillator circuitry. oscillator circuitry.
Figure 12-4. External Crystal Connections
) and the maximum rise and fall transition times (T
XLXX
MINIMUM HARDWARE CONSIDERATIONS
XTAL1 XTAL1
8XC196 8XC196
Device Device
XTAL2 XTAL2
Quartz Crystal Quartz Crystal
A0273-02
A0273-02
and T )
XLHX XHXL
12-7