
ML62Q1000 Series User's Manual
Chapter 6
Clock Generation Circuit
FEUL62Q1000
6-23
6.3.4 Switching of System Clock
Figure 6-13 shows the flow chart of the system clock switching (LSCLK
à
HSCLK).
Figure 6-13 Flow Chart of System Clock Switching (LSCLK
à
HSCLK)
[Note]
Ÿ
When the voltage of VDD is 1.6 V ≤ VDD < 1.8 V, set the system clock (SYSTEMCLK) and the high-speed
clock (HSCLK) to 4 MHz or below. If it exceeds 4 MHz, the operation is not guaranteed.
Choose the oscillation stabilization time of the high-speed
clock (HSCLK).
If a value other than the initial value is set, the frequency
accuracy is not guaranteed until approx. 2 ms has passed.
Oscillation only in low-speed clock
Enable oscillation of the high-speed clock to switch the system
clock to the high-speed clock. To switch the clock, follow either
of approaches below:
- If writing 0x03 to FCON register, the CPU will wait for the time
set in FHWUPT register.
- If writing 0x02 to FCON register, the CPU operates at
low-speed clock. Write 0x03 to the FCON register after waiting
for the high-speed oscillation stabilization time.
Set the frequency dividing ratio of the high-speed clock.
1/1 to 1/32 HSCLK can be chosen
Setting of FCON
Writing of FHCKMOD
Writing of FHWUPT
Voltage
1.6 V ≤ V
DD
<
1.8 V
V
DD
≧
1.8 V
High-speed operation mode
To (1)
Choose the oscillation stabilization time of the high-speed
clock (HSCLK).
If a value other than the initial value is set, the frequency
accuracy is not guaranteed until approx. 2 ms has passed.
1.6 V ≤ V
DD
<
1.8 V
Enable oscillation of the high-speed clock to switch the system
clock to the high-speed clock. To switch the clock, follow either
of the approaches below:
- If writing 0x03 to FCON register, the CPU will wait for the time
set in FHWUPT register.
- If writing 0x02 to FCON register, the CPU operates at
low-speed clock. Write 0x03 to the FCON register after waiting
for the high-speed oscillation stabilization time.
Set the frequency dividing ratio of the high-speed clock to 4
MHz or lower
Setting of FCON
Writing of FHCKMOD
Writing of FHWUPT
High-speed operation mode
If V
DD
is below 1.8 V, the frequency of the high-speed clock is
limited.
The system clock switches to the high-speed clock.
(1)
The system clock switches to the high-speed clock.
Содержание ML62Q1000 Series
Страница 17: ...Chapter 1 Overview...
Страница 112: ...Chapter 2 CPU and Memory Space...
Страница 154: ...Chapter 3 Reset Function...
Страница 166: ...Chapter 4 Power Management...
Страница 196: ...Chapter 5 Interrupts...
Страница 248: ...Chapter 6 Clock generation Circuit...
Страница 274: ...Chapter 7 Low Speed Time Base Counter...
Страница 291: ...Chapter 8 16 Bit Timer...
Страница 320: ...Chapter 9 Functional Timer FTM...
Страница 382: ...Chapter 10 Watchdog Timer...
Страница 402: ...Chapter 11 Serial Communication Unit...
Страница 456: ...Chapter 12 I2 C Bus Unit...
Страница 491: ...Chapter 13 I2 C Master...
Страница 512: ...Chapter 14 DMA Controller...
Страница 531: ...Chapter 15 Buzzer...
Страница 550: ...Chapter 16 Simplified RTC...
Страница 559: ...Chapter 17 GPIO...
Страница 594: ...Chapter 18 External Interrupt Function...
Страница 612: ...Chapter 19 CRC Generator...
Страница 632: ...Chapter 20 Analog Comparator...
Страница 644: ...Chapter 21 D A Converter...
Страница 655: ...Chapter 22 Voltage Level Supervisor...
Страница 676: ...Chapter 23 Successive Approximation Type A D Converter...
Страница 709: ...Chapter 24 Regulator...
Страница 714: ...Chapter 25 Flash Memory...
Страница 743: ...Chapter 26 Code Option...
Страница 750: ...Chapter 27 LCD Driver...
Страница 788: ...Chapter 28 On Chip Debug Function...
Страница 795: ...Chapter 29 Safety Function...
Страница 813: ...Appendix A...
Страница 881: ...Revision History...