Configuration Of Clock Generator - NEC 78K0 Series User Manual

(3) Internal low-speed oscillation clock (clock for watchdog timer)
• Internal low-speed oscillator
This circuit oscillates a clock of f
clock always starts operating.
Oscillation can be stopped by using the internal oscillation mode register (RCM) when "internal low-speed
oscillator can be stopped by software" is set by option byte.
The internal low-speed oscillation clock cannot be used as the CPU clock. The following hardware operates
with the internal low-speed oscillation clock.
• Watchdog timer
• TMH1 (when f
RL
Remark f : Internal low-speed oscillation clock frequency
RL

6.2 Configuration of Clock Generator

The clock generator includes the following hardware.
Item
Control registers
Oscillators
CHAPTER 6 CLOCK GENERATOR
= 240 kHz (TYP.). After a reset release, the internal low-speed oscillation
RL
7 9
, f /2 , or f /2 is selected)
RL RL
Table 6-1. Configuration of Clock Generator
Clock operation mode select register (OSCCTL)
Processor clock control register (PCC)
Internal oscillation mode register (RCM)
Main OSC control register (MOC)
Main clock mode register (MCM)
Oscillation stabilization time counter status register (OSTC)
Oscillation stabilization time select register (OSTS)
X1 oscillator
XT1 oscillator
Internal high-speed oscillator
Internal low-speed oscillator
Preliminary User's Manual U17260EJ3V1UD
Configuration
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