Toshiba TLCS-900/L1 Series Manual page 27

3.3
3.3.6 Noise Reduction Circuits
Noise reduction circuits are built in, allowing implementation of the following features.
(1) Reduced drivability for high-frequency oscillator
(2) Reduced drivability for low-frequency oscillator
(3) Single drive for high-frequency oscillator
(4) SFR protection of register contents
(5) ROM protection of register contents
(1) Reduced drivability for high-frequency oscillator
(Purpose)
Reduces noise and power for oscillator when a resonator is used.
(Block diagram)
C1
Resonator
C2
(Setting method)
The drivability of the oscillator is reduced by writing 0 to EMCCR0<DRVOSCH>
register. By reset, <DRVOSCH> is initialized to 1 and the oscillator starts oscillation
by normal-drivability when the power supply is on.
Don't set <DRVOSCH> to 0 at Vcc = 2 V ± 10%.
X1 pin
X2 pin
91C824-25
f
OSCH
(STOP + EMCCR0<EXTIN>)
Enable oscillation
EMCCR0<DRVOSCH>
TMP91C824
2008-02-20