upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 103

• Manufacturer Part Number: upd78f0730
• Description: 8-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

(2) Example of setting procedure when using internal high-speed oscillation clock as CPU clock and
(3) Example of setting procedure when stopping the internal high-speed oscillation clock
<1> • Restarting oscillation of the internal high-speed oscillation clock
<2> Selecting the clock supplied as the main system clock and peripheral hardware clock (MCM register)
<3> Selecting the CPU clock division ratio (PCC register)
The internal high-speed oscillation clock can be stopped in the following two ways.
• Executing the STOP instruction to set the STOP mode
• Setting RSTOP to 1 and stopping the internal high-speed oscillation clock
(a) To execute a STOP instruction
peripheral hardware clock
<1> Setting of peripheral hardware
<2> Setting the X1 clock oscillation stabilization time after standby release
• Oscillating the high-speed system clock
Set the main system clock and peripheral hardware clock using XSEL and MCM0.
Caution If the internal high-speed oscillation clock is selected as the main system clock, a clock
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.
(See 5.6.2 (1) Example of setting procedure when restarting internal high-speed oscillation
clock).
(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-
XSEL
CSS
Stop peripheral hardware that cannot be used in the STOP mode (for peripheral hardware that
cannot be used in STOP mode, see CHAPTER 14 STANDBY FUNCTION).
When the CPU is operating on the X1 clock, set the value of the OSTS register before the STOP
instruction is executed.
0
0
0
speed system clock is already operating.
other than the internal high-speed ocsillation clock cannot be set as the peripheral
hardware clock.
MCM0
PCC2
0
1
0
0
0
0
1
Other than above
Internal high-speed oscillation clock
(f
Selection of Main System Clock and Clock Supplied to Peripheral Hardware
RH
PCC1
)
Preliminary User’s Manual U19014EJ1V0UD
CHAPTER 5 CLOCK GENERATOR
0
0
1
1
0
Main System Clock (f
PCC0
0
1
0
1
0
Note
f
f
f
f
f
Setting prohibited
XP
XP
XP
XP
XP
XP
)
/2 (default)
/2
/2
/2
2
3
4
CPU Clock (f
Internal high-speed oscillation clock
(f
RH
Peripheral Hardware Clock (f
)
Note
CPU
) Selection
PRS
)
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