h8s-2635 Renesas Electronics Corporation., h8s-2635 Datasheet - Page 997

• Manufacturer Part Number: h8s-2635
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

22A.4 PLL Circuit
The PLL circuit has the function of multiplying the frequency of the clock from the oscillator by a
factor of 1, 2, or 4. The multiplication factor is set with the STC bits in SCKCR. The phase of the
rising edge of the internal clock is controlled so as to match that at the EXTAL pin.
When the multiplication factor of the PLL circuit is changed, the operation varies according to the
setting of the STCS bit in SCKCR.
When STCS = 0 (initial value), the setting becomes valid after a transition to software standby
mode, watch mode * , or subactive mode * . The transition time count is performed in accordance
with the setting of bits STS2 to STS0 in SBYCR.
[1] The initial PLL circuit multiplication factor is 1.
[2] A value is set in bits STS2 to STS0 to give the specified transition time.
[3] The target value is set in STC1 and STC0, and a transition is made to software standby mode,
[4] The clock pulse generator stops and the value set in STC1 and STC0 becomes valid.
[5] Software standby mode, watch mode * , or subactive mode * is cleared, and a transition time is
[6] After the set transition time has elapsed, the LSI resumes operation using the target
If a PC break is set for the SLEEP instruction that causes a transition to software standby mode in
[1], software standby mode is entered and break exception handling is executed after the
oscillation stabilization time. In this case, the instruction following the SLEEP instruction is
executed after execution of the RTE instruction.
When STCS = 1, the LSI operates on the changed multiplication factor immediately after bits
STC1 and STC0 are rewritten.
Note: * Subclock functions (subactive mode, subsleep mode, and watch mode) are available in the
watch mode * , or subactive mode * .
secured in accordance with the setting in STS2 to STS0.
multiplication factor.
Section 22A Clock Pulse Generator (H8S/2636 Group, H8S/2638 Group, H8S/2630 Group)
U-mask and W-mask versions only.
These functions cannot be used with the other versions.
Rev. 6.00 Feb 22, 2005 page 937 of 1484
REJ09B0103-0600