115
Direct transition time = { (Number of SLEEP instruction execution states) + (number of internal
processing states) }
×
(t
cyc
before transition) + (number of interrupt
exception handling execution states)
×
(t
cyc
after transition)
.................................. (2)
Example: Direct transition time = (2 + 1)
×
16t
osc
+ 14
×
2t
osc
= 76t
osc
(when /8 is selected as the
CPU operating clock)
Notation:
t
osc
:
t
cyc
:
OSC clock cycle time
System clock () 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) }
×
(t
subcyc
before transition) + { (wait time set in STS2
to STS0) + (number of interrupt exception handling execution states) }
×
(t
cyc
after transition)
........................ (3)
Example: Direct transition time = (2 + 1)
×
8t
w
+ (8192 + 14)
×
2t
osc
= 24t
w
+ 16412t
osc
(when
w/8 is selected as the CPU operating clock, and wait time = 8192 states)
Notation:
t
osc
:
t
w
:
t
cyc
:
t
subcyc
:
OSC clock cycle time
Watch clock cycle time
System clock () cycle time
Subclock (
SUB
) cycle time