HD6437020 Datasheet, PDF (107/507 Pages) Hitachi Semiconductor – SuperH™ RISC engine

External clock input
Open
XTAL
EXTAL
Figure 7.4 External Clock Input Method
t_cyc
t_EXH
t_EXL
1/2 V_cc
VIH
VIL
t_EXr
t_EXf
Figure 7.5 Input Clock Waveform
Table 7.3 Input Clock Specifications
t_EXr/f (V_IL–V_IH)
t_EXH/L (1/2 V_CC
standard)
5 V Specifications
(fmax = 20 MHz)
Max = 5
Min = 10
3.3 V Specifications
(fmax = 12.5 MHz)
Max = 10
Min = 20
Units
ns
ns
7.3 Usage Notes
Board design: When designing the board, place the crystal resonator and its load capacitors as
close as possible to the XTAL and EXTAL pins. Route no other signal lines near the XTAL and
EXTAL pin signal lines to prevent induction from interfering with correct oscillation. See figure
7.6.
HITACHI 91