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CHAPTER 5 CLOCK GENERATOR
User’s Manual U15798EJ2V0UD
5.3 Clock Generator Control Registers
The clock generator is controlled by the following two registers.
•
Processor clock control register (PCC)
•
Subclock select register (SSCK)
(1) Processor clock control register (PCC)
The clock generator is controlled by the processor clock control register (PCC).
PCC sets the CPU clock selection, the division ratio, main system clock oscillator operation/stop and whether
to use the subsystem clock oscillator internal feedback resistor
Note
.
PCC is set by a 1-bit or 8-bit memory manipulation instruction.
RESET input sets the value of PCC to 04H.
Note
The feedback resistor is necessary for adjusting the bias point of the oscillation waveform close to the
medium level of the supply voltage. The current consumption in the STOP mode can be further suppressed
by setting bit 6 (FRC) of PCC to 1 only when the subsystem clock is not used.
Figure 5-2. Subsystem Clock Feedback Resistor
FRC
P-ch
Feedback resistor
XT1
XT2
Содержание mPD780344 Series
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