h8s-2646 Renesas Electronics Corporation., h8s-2646 Datasheet - Page 793

• Manufacturer Part Number: h8s-2646
• Description: Renesas 16-bit Single-chip Microcomputer H8s Family/h8s/2600 Series
• Manufacturer: Renesas Electronics Corporation.

22.11
22.11.1 Overview of Direct Transitions
There are three modes, high-speed, medium-speed, and subactive, in which the CPU executes
programs. When a direct transition is made, there is no interruption of program execution when
shifting between high-speed and subactive modes. Direct transitions are enabled by setting the
LPWRCR DTON bit to 1, then executing the SLEEP instruction. After a transition, direct
transition interrupt exception processing starts.
Direct Transitions from High-Speed Mode to Subactive Mode: Execute the SLEEP instruction
in high-speed mode when the SBYCR SSBY bit = 1, LPWRCR LSON bit = 1, and DTON bit = 1,
and TSCR (WDT1) PSS bit = 1 to make a transition to subactive mode.
Direct Transitions from Subactive Mode to High-Speed Mode: Execute the SLEEP instruction
in subactive mode when the SBYCR SSBY bit = 1, LPWRCR LSON bit = 0, and DTON bit = 1,
and TSCR (WDT1) PSS bit = 1 to make a direct transition to high-speed mode after the time set in
SBYCR STS2 to STS0 has elapsed.
22.12
Output of the φ clock can be controlled by means of the PSTOP bit in SCKCR, and DDR for the
corresponding port. When the PSTOP bit is set to 1, the φ clock stops at the end of the bus cycle,
and φ output goes high. φ clock output is enabled when the PSTOP bit is cleared to 0. When DDR
for the corresponding port is cleared to 0, φ clock output is disabled and input port mode is set.
Table 22.6 shows the state of the φ pin in each processing state.
Table 22.6 φ φ φ φ Pin State in Each Processing State
DDR
PSTOP
Hardware standby mode
Software standby mode, watch
mode, and direct transition
Sleep mode and subsleep mode
High-speed mode, medium-speed
mode
Subactive mode
Direct Transitions
φ φ φ φ Clock Output Disabling Function
0
—
High impedance
High impedance
High impedance
High impedance
High impedance
Rev. 5.00 Sep 22, 2005 page 767 of 1136
1
0
High impedance
Fixed high
φ output
φ output
φ
SUB
output
Section 22 Power-Down Modes
1
1
High impedance
Fixed high
Fixed high
Fixed high
Fixed high
REJ09B0257-0500