UPD750104 Datasheet, PDF (23/80 Pages) NEC – 4 BIT SINGLE-CHIP MICROCONTROLLER

µPD750104, 750106, 750108, 750104(A), 750106(A), 750108(A)
6.3 Control Functions of Subsystem Clock Oscillator
The subsystem clock oscillator of the µPD750108 has two control functions to decrease the supply current.
• The function to select with the software whether to use the built-in feedback resistor^Note
• The function to suppress the supply current by reducing the drive current of the built-in inverter when the supply
voltage is high (VDD ≥ 2.7 V)
Note When the subsystem clock is not used, set SOS.0 to 1 (not to use the built-in feedback resistor), connect
XT1 to VSS or VDD, and open XT2. This makes it possible to reduce the supply current required by the
subsystem clock oscillator.
Each function can be used by switching bits 0 and 1 in the sub-oscillator control register (SOS). (See Figure 6-
2.)
Figure 6-2. Subsystem Clock Oscillator
SOS.0
Feedback resistor
Inverter
XT1
XT2
SOS.1
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