em78p156n ELAN Microelectronics Corp, em78p156n Datasheet - Page 27

• Manufacturer Part Number: em78p156n
• Description: 8-bit Micro-controller
• Manufacturer: ELAN Microelectronics Corp

EM78P156N 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 8 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.
2. Crystal Oscillator/Ceramic Resonators (XTAL)
Table 9 The Summary of Maximum Operating Speeds
Two cycles with two clocks
Conditions
Fig. 11 Circuit for External Clock Input
Fig. 12 Circuit for Crystal/Resonator
EM78P156N
EM78P156N
OSCO
OSCO
OSCI
27
OSCI
VDD
3.0
5.0
XTAL
RS
Fxt max.(MHz)
C1
C2
20.0
8.0
Ext. Clock
EM78P156N
OTP ROM
07.29.2004 (V1.2)