C517A_99 Datasheet, PDF (63/218 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

Reset / System Clock
C517A
To Internal
Timing Circuitry
XTAL1
*)
C₁
C₂
*) _{Crystal or ceramic resonator}
C517A
XTAL2
MCS03325
Figure 5-5
On-Chip Oscillator Circuiry
To drive the C517A with an external clock source, the external clock signal has to be applied to
XTAL2, as shown in figure 5-6. 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.
External
Clock
Signal
Figure 5-6
External Clock Source
V_VCDCD
N.C.
C517A
XTAL1
XTAL2
MCS03326
Semiconductor Group
5-7