Fujitsu FR81S User Manual
CHAPTER 5: CLOCK
5. Operation
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : CLOCK
FUJITSU SEMICONDUCTOR CONFIDENTIAL
65
The clock gear begins (CCCGRCR0.GRSTR=1)
↓
Verifies that the clock gear high-speed oscillation is stopped (CCCGRCR0.GRSTS[1:0]=10)
↓
While selecting PLL/SSCG clock as the source clock (CMONR.CKM[1:0]=10)
2. PLL/SSCG clock→the main clock divided by 2
While selecting PLL/SSCG clock as the source clock (CMONR.CKM[1:0]=10)
↓
Clock gear begins (CCCGRCR0.GRSTR=1)
↓
Verifies that the clock gear low-speed oscillation is stopped (CCCGRCR0.GRSTS[1:0]=00)
↓
Switches the source clock to the main clock divided by 2 (CSELR.CKS[1:0]=10→00)
↓
While selecting the main clock as the source clock (CMONR.CKM[1:0]=00)
3. the main clock divide by 2→sub clock
While selecting the main clock divided by 2 as the source clock (CMONR.CKM[1:0]=01)
↓
Sets the sub clock oscillation stabilization wait time (sets CSTBR.SOSW[2:0])
–when sub oscillation is not enabled–
↓
Clears the sub timer interrupt source (STIF=0)
↓
(as necessary) sets sub timer interrupt enable (STIE=1)
↓
In a single clock product, selecting the CR clock as a sub-clock source
↓
The sub clock oscillation begins (SCEN=0→1)
↓
Sub clock oscillation stabilization wait loop (loop until when SCRDY=1), or interrupt wait
↓
Clears sub timer interrupt (STIF=0)
↓
MB91520 Series
MN705-00010-1v0-E
226