NEC PD750008 User Manual
Page 112
92
µPD750008 USER'S MANUAL
(4) Frequency divider
The frequency divider divides the output (f
X
) of the main system clock oscillator to generate various clocks.
(5) Control functions of subsystem clock oscillator
The subsystem clock oscillator of the µPD750008 subseries has two control functions to decrease the
supply current.
• The function to select with the software whether to use the built-in feedback resistor
• The function to suppress the supply current by reducing the drive current of the built-in inverter when
the operating supply voltage is high (V
DD
• 2.7 V)
Each function can be used by switching bits 0 and 1 in the sub-oscillator control register (SOS). (See
Figure 5-17.)
Figure 5-17. Subsystem Clock Oscillator
SOS.0
SOS.1
XT1
XT2
Inverter
Feedback resistor
µPD750008