Chapter 5 Clock Generator; Functions Of Clock Generator; Configuration Of Clock Generator - NEC MuPD78F0132H User Manual

5.1 Functions of Clock Generator

The clock generator generates the clock to be supplied to the CPU and peripheral hardware.
The following three system clock oscillators are available.
• High-speed system clock oscillator
The high-speed system clock oscillator oscillates a clock of f
by executing the STOP instruction or setting the main OSC control register (MOC) and processor clock control
register (PCC).
• Ring-OSC oscillator
The Ring-OSC oscillator oscillates a clock of f
Ring-OSC mode register (RCM) when "Can be stopped by software" is set by the option byte and the high-
speed system clock is used as the CPU clock.
• Subsystem clock oscillator
The subsystem clock oscillator oscillates a clock of f
subsystem clock oscillator is not used, setting not to use the on-chip feedback resistor is possible using the
processor clock control register (PCC), and the operating current can be reduced in the STOP mode.
Remarks 1. f : High-speed system clock oscillation frequency
XP
2. f : Ring-OSC clock oscillation frequency
R
3. f : Subsystem clock oscillation frequency
XT

5.2 Configuration of Clock Generator

The clock generator includes the following hardware.
Item
Control registers
Oscillators

CHAPTER 5 CLOCK GENERATOR

= 240 kHz (TYP.). Oscillation can be stopped by setting the
R
Table 5-1. Configuration of Clock Generator
Processor clock control register (PCC)
Ring-OSC mode register (RCM)
Main clock mode register (MCM)
Main OSC control register (MOC)
Oscillation stabilization time counter status register (OSTC)
Oscillation stabilization time select register (OSTS)
High-speed system clock oscillator
Ring-OSC oscillator
Subsystem clock oscillator
User's Manual U16899EJ2V0UD
= 2.0 to 16.0 MHz. Oscillation can be stopped
XP
= 32.768 kHz. Oscillation cannot be stopped. When
XT
Configuration
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