NEC mPD780065 Series, Preliminary User'S Manual

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Preliminary User’s Manual U13420EJ2V0UM00
CHAPTER 5 CLOCK GENERATOR
5.1 Clock Generator Functions
The clock generator generates the clock to be supplied to the CPU and peripheral hardware. The following two
types of system clock oscillators are available.
(1) Main system clock oscillator
This circuit oscillates at frequencies of 1 to 8.38 MHz. Oscillation can be stopped by executing the STOP
instruction or setting the processor clock control register (PCC).
(2) Subsystem clock oscillator
The circuit oscillates at a frequency of 32.768 kHz. Oscillation cannot be stopped. If the subsystem clock oscillator
is not used, the internal feedback resistor can be disabled by the processor clock control register (PCC). This
enables to reduce the power dissipation in the STOP mode.
5.2 Clock Generator Configuration
The clock generator consists of the following hardware.
Table 5-1. Clock Generator Configuration
Item Configuration
Control register Processor clock control register (PCC)
Oscillator Main system clock oscillator
Subsystem clock oscillator