
8. Clock Generation Circuits
Figure 8.1
Clock Generation Circuit
1/2
fROC
CM05
PM26
XIN
XOUT
fXIND
fROC
1/2n
1/8
1/4
fAD
f1
f8
f32
f2n(1)
PM27 and PM26
CM21
CM17
PM35(4)
CST
1/m(2)
1/2
CM21
CM05
BCLK
CPU
clock
Output to verify
interrupt request level
Software
reset
RESET
NMI
WAIT instruction
(wait mode)
SQ
R
SQ
R
CM10=1 (stop mode)
1/32
fC32
XCIN
XCOUT
CM02
CM04
CM07
1
0
1
0
10
00
1
0
1
0
1
0
01
CM00, CM01, CM02, CM04, CM05, CM07: Bits in the CM0 register
CM10, CM17: Bits in the CM1 register
CM21: Bit in the CM2 register
PM26, PM27: Bits in the PM2 register
CST: Bit in the TCSPR register
CPSR: Bit in the CPSRF register
CLKOUT
11
10
01
00
Port P5_3
fC
f8
f32
Peripheral function clock
CM01 and CM00
(3)
Sub clock oscillation circuit
Main clock oscillation circuit
Main clock
Peripheral function
clock source (fPFC)
ab
cd
PLL
frequency
synthesizer
On-chip
oscillator
Clock edge detect/
charge and discharge
circuit control
Charge and
discharge circuit
Oscillation stop
detection interrupt
request generation
circuit
Watchdog timer
interrupt request
On-chip oscillator circuit
Interrupt request signal
On-chip oscillator clock (fROC)
CM21 bit switch signal
b
a
On-chip oscillator
PLL frequency Synthesizer
Programmable
counter
Reference
frequency counter
Phase
comparator
Charge
pump
Voltage
controlled
oscillator
(VCO)
1/2
c
d
PLL clock (fPLL)
CPSR=1
Divider
reset
fXIND
NOTES:
1. Bits CNT3 to CNT0 in the TCSPR register select no division (n = 0) or divide-by-2n (n = 1 to 15).
2. Bits MCD4 to MCD0 in the MCD register select divide-by-m (m = 1, 2, 3, 4, 6, 8, 10, 12, 14, 16 ).
3. When both the PM37 bit in the PM3 register and the CM17 bit in the CM1 register are set to 1, they are set to 1.
Other combinations are set to 0.
4. To use the PLL clock as the clock source for the CPU clock and peripheral function clock, set the PM35 bit in the
PM3 register to 1 (fPFC divided by 2).
Peripheral function clock