2.
Time for direct transition from active (medium-speed) mode to active (high-speed) mode
A direct transition from active (medium-speed) mode to active (high-speed) mode is performed by
executing a SLEEP instruction in active (medium-speed) mode while bits SSBY and LSON are both
cleared to 0 in SYSCR1, and bit MSON is cleared to 0 and bit DTON is set to 1 in SYSCR2. The
time from execution of the SLEEP instruction to the end of interrupt exception handling (the direct
transition time) is given by equation (2) below.
Direct transition time = { (Number of SLEEP instruction execution states) + (number of internal
processing states) }
×
(tcyc before transition) + (number of interrupt
exception handling execution states)
×
(tcyc after transition)
.................................. (2)
Example: Direct transition time = (2 + 1)
×
14
×
2tosc = 76tosc (when ø/8 is selected as
the CPU operating clock)
Notation:
tosc:
OSC clock cycle time
tcyc: System clock (ø) cycle time
3.
Time for direct transition from subactive mode to active (high-speed) mode
A direct transition from subactive mode to active (high-speed) mode is performed by executing a
SLEEP instruction in subactive mode while bit SSBY is set to 1 and bit LSON is cleared to 0 in
SYSCR1, bit MSON is cleared to 0 and bit DTON is set to 1 in SYSCR2, and bit TMA3 is set to 1
in TMA. The time from execution of the SLEEP instruction to the end of interrupt exception
handling (the direct transition time) is given by equation (3) below.
Direct transition time = { (Number of SLEEP instruction execution states) + (number of internal
processing states) }
×
(tsubcyc before transition) + { (wait time set in STS2
to STS0) + (number of interrupt exception handling execution states) }
×
(tcyc after transition)
........................ (3)
112