NEC switch - Manual (Page 73)

User’s Manual U12978EJ3V0UD
73
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 type
of system clock oscillator is used.
•••• System clock oscillator
This circuit oscillates at 6.0 MHz. Oscillation can be stopped by executing the STOP instruction.
5.2 Clock Generator Configuration
The clock generator consists of the following hardware.
Table 5-1. Configuration of Clock Generator
Item Configuration
Control register Processor clock control register (PCC)
Oscillator System clock oscillator
Figure 5-1. Block Diagram of Clock Generator
Prescaler
System
clock oscillator
f X
Prescaler
Standby
controller Wait
controller
CPU clock (f
CPU
)
STOP
f X
2 2
Clock for peripheral
hardware
PCC1
Internal bus
Processor clock
control register (PCC)
X1
X2
Selector