upd78f0730 Renesas Electronics Corporation., upd78f0730 Datasheet - Page 102

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

5.6.2 Example of controlling internal high-speed oscillation clock
102
The following describes examples of clock setting procedures for the following cases.
(1) When restarting oscillation of the internal high-speed oscillation clock
(2) When using internal high-speed oscillation clock as CPU clock, and internal high-speed oscillation clock or
(3) When stopping the internal high-speed oscillation clock
(1) Example of setting procedure when restarting oscillation of the internal high-speed oscillation clock
(b) To stop X1 oscillation (disabling external clock input) by setting MSTOP to 1
high-speed system clock as peripheral hardware clock
<1> Setting restart of oscillation of the internal high-speed oscillation clock (RCM register)
<2> Waiting for the oscillation accuracy stabilization time of internal high-speed oscillation clock (RCM
Notes 1. After a reset release, the internal high-speed oscillator automatically starts oscillating and the
<1> Confirming the CPU clock status (PCC and MCM registers)
<2> Stopping the high-speed system clock (MOC register)
Caution Be sure to confirm that MCS = 0 or CLS = 1 when setting MSTOP to 1. In addition, stop
When RSTOP is cleared to 0, the internal high-speed oscillation clock starts operating.
register)
Wait until RSTS is set to 1
Confirm with CLS and MCS that the CPU is operating on a clock other than the high-speed system clock.
2. This wait time is not necessary if high accuracy is not necessary for the CPU clock and peripheral
CLS
0
0
When CLS = 0 and MCS = 1, the high-speed system clock is supplied to the CPU, so change the
CPU clock to the internal high-speed oscillation clock.
When MSTOP is set to 1, X1 oscillation is stopped (the input of the external clock is disabled).
internal high-speed oscillation clock is selected as the CPU clock.
hardware clock.
peripheral hardware that is operating on the high-speed system clock.
MCS
1
0
Internal high-speed oscillation clock
High-speed system clock
Note 2
Preliminary User’s Manual U19014EJ1V0UD
CHAPTER 5 CLOCK GENERATOR
.
CPU Clock Status
Note 1