UPD78F0411GA-GAM-AX Datasheet, PDF (132/564 Pages) Renesas Technology Corp – Old Company Name in Catalogs and Other Documents

CHAPTER 5 CLOCK GENERATOR
(1) Example of setting procedure when restarting oscillation of the internal high-speed oscillation clock^{Note 1}
<1> Setting restart of oscillation of the internal high-speed oscillation clock (RCM register)
When RSTOP is cleared to 0, the internal high-speed oscillation clock starts operating.
<2> Waiting for the oscillation accuracy stabilization time of internal high-speed oscillation clock (RCM
register)
Wait until RSTS is set to 1^{Note 2}.
Notes 1. After a reset release, the internal high-speed oscillator automatically starts oscillating and the
internal high-speed oscillation clock is selected as the CPU clock.
2. This wait time is not necessary if high accuracy is not necessary for the CPU clock and peripheral
hardware clock.
(2) Example of setting procedure when using internal high-speed oscillation clock as CPU clock, and
internal high-speed oscillation clock or high-speed system clock as peripheral hardware clock
<1> • Restarting oscillation of the internal high-speed oscillation clock^Note
(See 5.6.2 (1) Example of setting procedure when restarting oscillation of the internal high-
speed oscillation clock).
• Oscillating the high-speed system clock^Note
(This setting is required when using the high-speed system clock as the peripheral hardware clock.
See 5.6.1 (1) Example of setting procedure when oscillating the X1 clock and (2) Example of
setting procedure when using the external main system clock.)
Note The setting of <1> is not necessary when the internal high-speed oscillation clock or high-
speed system clock is already operating.
<2> Selecting the clock supplied as the main system clock and peripheral hardware clock (MCM register)
Set the main system clock and peripheral hardware clock using XSEL and MCM0.
XSEL
0
0
1
MCM0
0
1
0
Selection of Main System Clock and Clock Supplied to Peripheral Hardware
Main System Clock (fXP)
Peripheral Hardware Clock (fPRS)
Internal high-speed oscillation clock Internal high-speed oscillation clock
(fRH)
(fRH)
High-speed system clock (fXH)
<3> Selecting the CPU clock division ratio (PCC register)
When CSS is cleared to 0, the main system clock is supplied to the CPU. To select the CPU clock
division ratio, use PCC0, PCC1, and PCC2.
CSS
0
PCC2
PCC1
PCC0
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
Other than above
CPU Clock (fCPU) Selection
fXP
fXP/2 (default)
fXP/2²
fXP/2³
fXP/2⁴
Setting prohibited
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User’s Manual U18698EJ1V0UD