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CHAPTER 5 CLOCK GENERATOR
User’s Manual U15104EJ2V0UD
5.5 Clock Generator Operations
The clock generator generates the following types of clocks and controls the CPU operating mode, such as
the standby mode.
• System clock f
X
• CPU clock f
CPU
• Clock to peripheral hardware
The following clock generator functions and operations are determined by the processor clock control register
(PCC).
(a) Upon generation of the RESET signal, the lowest speed mode of the system clock (7.11
µ
s when operated
at 4.5 MHz) is selected (PCC = 04H). System clock oscillation stops while a low level is applied to the RESET
pin.
(b) One of the five CPU clock types (0.45, 0.89, 1.78, 3.56, 7.11
µ
s at 4.5 MHz) can be selected by setting PCC.
(c) Two standby modes, STOP and HALT, are available.
(d) The system clock is divided and supplied to the peripheral hardware. The peripheral hardware also stops if
the system clock is stopped.
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