Elan EM78P156EL Manual page 26

Table 9 The Summary of Maximum Operating Speeds
Two cycles with two clocks
2. Crystal Oscillator/Ceramic Resonators (XTAL)
EM78P156EL can be driven by an external clock signal through the OSCI pin as shown in Fig. 11
below.
In the most applications, pin OSCI and pin OSCO can connected with a crystal or ceramic resonator
to generate oscillation. Fig. 12 depicts such circuit. The same thing applies whether it is in the HXT
mode or in the LXT mode. Table 10 provides the recommended values of C1 and C2. Since each
resonator has its own attribute, user should refer to its specification for appropriate values of C1 and
C2. RS, a serial resistor, may be necessary for AT strip cut crystal or low frequency mode.
This specification is subject to change without prior notice.
Conditions
OSCI
OSCO
EM78P156EL
Fig. 11 Circuit for External Clock Input
OSCI
EM78P156EL
OSCO
Fig. 12 Circuit for Crystal/Resonator
VDD Fxt max.(MHz)
2.3
3.0
5.0
Ext. Clock
C1
XTAL
C2
RS
26
EM78P156EL
4.0
8.0
20.0
OTP ROM
2002/04/19