External Clock Input - Hitachi SH7032 Hardware Manual

7.2.2

External Clock Input

An external clock signal can be input at the EXTAL pin as shown in figure 7.4. The XTAL pin
should be left open. The frequency must be equal to the system clock (CK) frequency. The
specifications for the waveform of the external clock input are given below. Make the external
clock frequency the same as the system clock (CK).
External clock input
1/2 V
cc
V
Table 7.3 Input Clock Specifications
5 V Specifications
(fmax = 20 MHz) *
t (V –V ) Max = 5
EXr/f IL IH
t Min = 10
EXH/L
Notes: *1 Except SH7034B
*2 SH7034B only
Figure 7.4 External Clock Input Method
t
EXH
V
IH
IL
t
EXr
Figure 7.5 Input Clock Waveform
3.3 V Specifications
1
(fmax = 12.5 MHz)
Max = 10
Min = 20
Open
t
cyc
t
EXL
t
EXf
3.3 V Specifications
(fmax = 20 MHz) *
Max = 5
Min = 15
XTAL
EXTAL
2
Unit
ns
ns
97