C868_02 Datasheet, PDF (177/244 Pages) Infineon Technologies AG – 8 - Bit CMOS Microcontroller

C868
Reset and System Clock Operation
XTAL1
*)
C₁
C₂
C868
XTAL2
To internal
timing circuitry
*) Crystal or ceramic resonator
Figure 5-6 On-Chip Oscillator Circuitry
To drive the C868 with an external clock source, the external clock signal has to be
applied to XTAL2, as shown in Figure 5-7. XTAL1 has to be left unconnected. A pullup
resistor is suggested (to increase the noise margin), but is optional if V_OH of the driving
gate corresponds to the V_IH2 specification of XTAL2.
V_DDC
N.C.
C868
XTAL1
External
Clock
Signal
XTAL2
Figure 5-7 External Clock Source
User’s Manual
5-11
V 0.4, 2002-01