EM78P156N

OTP ROM

Table 9 The Summary of Maximum Operating Speeds

Conditions

VDD

Fxt max.(MHz)

Two cycles with two clocks

3.0

8.0

 

 

5.0

20.0

 

 

 

 

2. Crystal Oscillator/Ceramic Resonators (XTAL)

EM78P156N can be driven by an external clock signal through the OSCI pin as shown in Fig. 11 below.

OSCI Ext. Clock

OSCO

EM78P156N

Fig. 11 Circuit for External Clock Input

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.

C1

OSCI

EM78P156N

XTAL

OSCO

RS C2

Fig. 12 Circuit for Crystal/Resonator

This specification is subject to change without prior notice. 27

07.29.2004 (V1.2)