Toshiba – Toshiba TMP87CP24AF User Manual
Page 23
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TOSHIBA
TMP87CM24A/P24A
b. Edge-sensitive release mode (RELM = 0)
In this mode, STOP mode is released by a rising edge of the STOP pin input. This is used in
applications
where
a
relatively
short
program
is
executed
repeatedly
at
periodic
intervals.
This
periodic
signal
(for
example,
a
clock
from
a
low-power
consumption
oscillator)
is
input
to
the
STOP pin.
In the edge-sensitive release mode, STOP mode is started even when the STOP pin input is high.
Example : Starting STOP mode operation in the edge-sensitive release mode
LD
(SYSCR1), 10000000B ;
OUTEN 0 (specifies high-impedance)
DI
IMF <-0 (disables interrupt service)
SET
(SYSCRI).STOP ;
STOP
<r
-1
(activates stop mode)
LDW
(IL),1110011101010111B ;
IL12,11,7, 5,3<-0
(clears interrupt latches)
El
;
IMF<-1 (enables interrupt service)
STOP mode is released by the following sequence:
©
When
returning
to
NORMAL2,
both
the
high-frequency
and
low-frequency
clock
oscillators
are
turned
on
;
when
returning
to
SLOW
mode,
only
the
low-frequency
clock
oscillator
is
turned
on. When returning to NORMAL 1, only the high-frequency clock oscillator is turned on.
@
A
warming-up
period
is
inserted
to
allow
oscillation
time
to
stabilize.
During
warm-up,
all
internal
operations
remain
halted.
Two
different
warming-up
times
can
be
selected
with
WUT
(bits 2 and 3 in SYSCR1) as determined by the resonator characteristics.
(3)
When
the
warming-up
time
has
elapsed,
normal
operation
resumes
with
the
instruction
following
the
STOP
mode
start
instruction
(e.g.
[SET
(SYSCR1).
7]).
The
start
is
made
after
the
divider of the timing generator is cleared to "
0
".
Table 1-1. Warming-up Time example
Return to NORMALI mode
Return to SLOW mode
WUT
At fc = 4.194304 MHz
At fc =
8
MHz
WUT
At fs = 32.768 kHz
3
X
2’7fc
[s]
2’7fc
375 [ms]
125
196.6 [ms]
65.5
3
X
2’7fs [s]
2’7fs
750 [ms]
250
Note:
The warming-up time is obtained by dividing the basic clock by the divider: therefore,
the warming-up time may include a certain amount of error if there is any fluctuation
of the oscillation frequency when STOP mode is released. Thus, the warming-up time
must be considered an approximate value.
STOP
mode
can
also
be
released
by
setting
the
RESET
pin
low,
which
immediately
performs
the
normal reset operation. In this case, even if the setting is to return to the SLOW mode, it starts
from
the
NORMAL
mode.
(If
the
initial
XTEN
of
TMP87CM24A/P24A
are
set
to
"1"
by
mask
option,
they
start
from
the
NORMAL2
mode.
In
case
of
TMP87PP24,
starts
from
NORMAL1
mode.
3
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24-23
2002
-
10-03