GMS81504 Datasheet, PDF (43/54 Pages) List of Unclassifed Manufacturers – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
GMS81504
OSCILLATOR CIRCUIT
XIN and XOUT are the input and output, respectively,
of a inverting amplifier which can be configured for
use as an on-chip oscillator, as shown in Figure 37.
C1
XOUT
C2
XIN
VSS
Recommend:
C1,C2 = 30 pF ± 10 pF for Crystals.
Figure 37. Oscillator Connections
To drive the device from an external clock source,
XOUT should be left unconnected while XIN is driven
as shown in Figure 39. There are no requirements on
the duty cycle of the external clock signal, since the
input to the internal clocking circuitry is through a
divide-by-two flip-flop, but minimum and maximum
high and low times specified on the data sheet must be
observed.
VSS
XIN
XOUT
RESET
R00
R01
Figure 38. Layout of Crystal
Oscillation circuit is designed to be used either with a
ceramic resonator or crystal oscillator. Since each crys-
tal and ceramic resonator have their own charac-
teristics, the user should consult the crystal
manufacturer for appropriate values of external com-
ponents.
In addition, see Figure 38. for the layout of the crystal.
In all cases, an external clock operation is available.
N/C
EXTERNAL
OSCILLATOR
SIGNAL
XOUT
XIN
VSS
Figure 39. External Clock Drive
Configuration
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