SH7280 Datasheet, PDF (122/1726 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperHTM RISC engine family

Section 4 Clock Pulse Generator (CPG)
4.8.2 Input of an External 48-MHz Clock Signal
Figure 4.6 shows an example of the connections for input of an external 48-MHz clock signal. The
USBXTAL pin must be left open.
USBEXTAL
Input external clock
USBXTAL
Open state
Figure 4.6 Example of Connecting an External 48-MHz Clock
Table 4.7 shows the input conditions for the external 48-MHz clock.
Table 4.7 Input Conditions for the External 48-MHz Clock
Item
Frequency (48 MHz)
Clock rise time
Clock fall time
Duty (t_HIGH/t_FREQ)
Symbol
t
FREQ
t
R48
t_F48
t_DUTY
Min.
47.88
—
—
40
Max.
48.12
3
3
60
Unit
MHz
ns
ns
%
Reference Figure
Figure 4.7
USBEXTAL
90%
10%
t_HIGH
t_FREQ
t_LOW
V_CC×5
t_R48
t_F48
Figure 4.7 Input Timing of External 48-MHz Clock
Rev. 1.00 Jun. 26, 2008 Page 92 of 1692
REJ09B0393-0100