103
Time for Direct Transfer from Subactive Mode to Active (High-Speed) Mode: When a
SLEEP instruction is executed in subactive mode while the SSBY bit in SYSCR1 is set to 1,
the LSON bit in SYSCR1 is cleared to 0, the MSON bit in SYSCR2 is cleared to 0, the
DTON bit in SYSCR2 is set to 1, and bit TMA3 in TMA is set to 1, a transition is made
directly to active (high-speed) mode. In this case, the time from execution of the SLEEP
instruction to the end of interrupt exception handling (the direct transfer time) is given by
equation (3) below:
Direct transfer time ={ (Number of SLEEP instruction execution states) +
(number of internal processing states) }
×
(t
subcyc
before transition) +
{ (standby time set in STS2 to STS0) +
(number of interrupt exception handling execution states) }
×
(t
cyc
after transition) ...................................................................... (3)
Example: H8/3637 Series direct transfer time = (2 + 1)
×
8t
w
+ (8192 + 14)
×
2t
osc
= 24t
w
+
16412t
osc
(When ø
w
/8 CPU operating clock and 8192-state standby time are selected)
Legend:
t
osc
: OSC clock cycle time
t
w
: Watch clock cycle time
t
cyc
: System clock (ø) cycle time
t
subcyc
: Subclock (ø
SUB
) cycle time
Time for Direct Transfer from Subactive Mode to Active (Medium-Speed) Mode: When
a SLEEP instruction is executed in subactive mode while the SSBY bit in SYSCR1 is set to 1,
the LSON bit in SYSCR1 is cleared to 0, the MSON bit in SYSCR2 is set to 1, the DTON bit
in SYSCR2 is set to 1, and bit TMA3 in TMA is set to 1, a transition is made directly to active
(medium-speed) mode. In this case, the time from execution of the SLEEP instruction to the
end of interrupt exception handling (the direct transfer time) is given by equation (4) below:
Direct transfer time ={ (Number of SLEEP instruction execution states) +
(number of internal processing states) }
×
(t
subcyc
before transition) +
{ (standby time set in STS2 to STS0) +
(number of interrupt exception handling execution states) }
×
(t
cyc
after transition) ...................................................................... (4)
Example: H8/3637 Series direct transfer time = (2 + 1)
×
8t
w
+ (8192 + 14)
×
16t
osc
= 24t
w
+
13129t
osc
(When ø
w
/8 CPU operating clock and 8192-state standby time are selected)
Legend:
t
osc
: OSC clock cycle time
t
w
: Watch clock cycle time
t
cyc
: System clock (ø) cycle time
t
subcyc
: Subclock (ø
SUB
) cycle time