Chapter 7 Clock Generator ( Μ Pd789124, 789134 Subseries); Function Of Clock Generator; Configuration Of Clock Generator - NEC mPD789101 User Manual

CHAPTER 7 CLOCK GENERATOR ( µ PD789124, 789134 SUBSERIES)

7.1 Function of Clock Generator

The clock generator generates the clock to be supplied to the CPU and peripheral hardware. The system clock
oscillator consists of the following type.
• System clock (RC) oscillator
This circuit oscillates at frequencies of 2.0 to 4.0 MHz. Oscillation can be stopped by executing the STOP
instruction.

7.2 Configuration of Clock Generator

The clock generator consists of the following hardware.
Item
Control register Processor clock control register (PCC)
Oscillator RC oscillator
CL1
System clock
oscillator
CL2
STOP
Table 7-1. Configuration of Clock Generator
Figure 7-1. Block Diagram of Clock Generator
Prescaler
f
CC
f
CC
2
2
PCC1
Processor clock control register (PCC)
Internal bus
User's Manual U13045EJ2V0UM00
Configuration
Prescaler
Standby
Wait control
control
circuit
circuit
Clock to peripheral
hardware
CPU clock (f )
CPU
95