SH7727 Datasheet, PDF (334/1109 Pages) Renesas Technology Corp – Renesas 32-Bit RISC Microcomputer SuperH RISC engine Family/SH7700 Series

Section 10 On-Chip Oscillation Circuits
10.3 Clock Operating Modes
Table 10.3 shows the relationship between the mode control pin (MD2 to MD0) combinations and
the clock operating modes. Table 10.4 shows the usable frequency ranges in the clock operating
modes.
Table 10.3 Clock Operating Modes
Pin Values
Mode MD2 MD1 MD0
0
0
0
0
Clock I/O
Source Output
EXTAL CKIO
1
0
0
1
EXTAL CKIO
2
0
1
0
Crystal CKIO
oscillator
7
1
1
1
CKIO —
PLL2 PLL1
On/Off On/Off
On,
On
multi-
plication
ratio: 1
On,
On
multi-
plication
ratio: 4
On,
On
multi-
plication
ratio: 4
Off
On
Divider 1 Divider 2 CKIO
Input
Input
Frequency
PLL1
output
PLL1
(EXTAL)
PLL1
output
PLL1
(EXTAL) × 4
PLL1
output
PLL1
(Crystal) × 4
PLL1
output
PLL1
(CKIO)
Mode 0: An external clock is input from the EXTAL pin and undergoes waveform shaping by
PLL circuit 2 before being supplied inside this LSI. PLL circuit 1 is constantly on. An input clock
frequency of 24 MHz to the maximum frequency of CKIO can be used. For details on the CKIO
maximum frequency, see section 32, Electrical Characteristics.
Mode 1: An external clock is input from the EXTAL pin and its frequency is multiplied by 4 by
PLL circuit 2 before being supplied inside this LSI, allowing a low-frequency external clock to be
used. An input clock frequency of 6 MHz to1/4 of the maximum frequency of CKIO can be used.
For details on the CKIO maximum frequency, see section 32, Electrical Characteristics.
Mode 2: The on-chip crystal oscillator operates, with the oscillation frequency being multiplied
by 4 by PLL circuit 2 before being supplied inside this LSI, allowing a low crystal frequency to be
used. A crystal oscillation frequency of 6 MHz to 1/4 of the maximum frequency of CKIO can be
used. For details on the CKIO maximum frequency, see section 32, Electrical Characteristics.
Rev. 5.00 Dec 12, 2005 page 262 of 1034
REJ09B0254-0500