C541U_99 Datasheet, PDF (45/192 Pages) Siemens Semiconductor Group – 8-BIT CMOS MICROCONTROLLER

Reset / System Clock
C541U
To Internal
Timing Circuitry
XTAL2
12 MHz
XTAL1
C540U
C541U
C₁
C₂
MCD03395
Figure 5-6
On-Chip Oscillator Circuiry
To drive the C541U with an external clock source, the external clock signal has to be applied to
XTAL1, as shown in figure 5-7. XTAL2 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 XTAL1.
External
Clock
Signal
Figure 5-7
External Clock Source
C541U
V_DD
N.C.
XTAL2
XTAL1
Semiconductor Group
5-8
1997-10-01