NEC mPD789426 Series, User Manual

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User’s Manual U15075EJ1V0UM00
103
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 used.
••••
Main system clock oscillator
This circuit oscillates at 1.0 to 5.0 MHz. Oscillation can be stopped by executing the STOP instruction or
setting the processor clock control register (PCC).
••••
Subsystem clock oscillator
This circuit oscillates at 32.768 kHz. Oscillation can be stopped by the suboscillation mode register (SCKM).
5.2 Clock Generator Configuration
The clock generator includes the following hardware.
Table 5-1. Configuration of Clock Generator
Item Configuration
Control registers Processor clock control register (PCC)
Suboscillation mode register (SCKM)
Subclock control register (CSS)
Oscillators Main system clock oscillator
Subsystem clock oscillator