TMP86CH29BUG Datasheet, PDF (34/196 Pages) Toshiba Semiconductor – 8 Bit Microcontroller

2. Operational Description
2.2 System Clock Controller
TMP86CH29BUG
STOP mode is released by the following sequence.
1. In the dual-clock mode, when returning to NORMAL2, both the high-frequency and low-
frequency clock oscillators are turned on; when returning to SLOW1 mode, only the low-
frequency clock oscillator is turned on. In the single-clock mode, only the high-frequency
clock oscillator is turned on.
2. A warm-up period is inserted to allow oscillation time to stabilize. During warm up, all
internal operations remain halted. Four different warm-up times can be selected with the
SYSCR1<WUT> in accordance with the resonator characteristics.
3. When the warm-up time has elapsed, normal operation resumes with the instruction follow-
ing the STOP mode start instruction.
Note 1: When the STOP mode is released, the start is made after the prescaler and the divider of the
timing generator are cleared to "0".
Note 2: STOP mode can also be released by inputting low level on the RESET pin, which immediately
performs the normal reset operation.
Note 3: When STOP mode is released with a low hold voltage, the following cautions must be observed.
The power supply voltage must be at the operating voltage level before releasing STOP mode.
The RESET pin input must also be “H” level, rising together with the power supply voltage. In this
case, if an external time constant circuit has been connected, the RESET pin input voltage will
increase at a slower pace than the power supply voltage. At this time, there is a danger that a
reset may occur if input voltage level of the RESET pin drops below the non-inverting high-level
input voltage (Hysteresis input).
Table 2-2 Warm-up Time Example (at fc = 16.0 MHz, fs = 32.768 kHz)
WUT
00
01
10
11
Warm-up Time [ms]
Return to NORMAL Mode
Return to SLOW Mode
12.288
750
4.096
250
3.072
5.85
1.024
1.95
Note 1: The warm-up time is obtained by dividing the basic clock by the divider. Therefore, the warm-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 warm-up time must be considered as an approximate
value.
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