Renesas R8C/20 User Manual

R8C/20 Group, R8C/21 Group 10. Clock Generation Circuit
Rev.2.00 Aug 27, 2008 Page 65 of 458
REJ09B0250-0200
Figure 10.1 Clock Generation Circuit
a
b
c
d
e
g
f1
f2
f4
f8
f32
h
S
Q
R
1/2 1/2
1/2 1/2 1/2
S
Q
R
FRA00
FRA01 = 1
FRA01 = 0
CM14
Power-on
reset
CPU clock
OCD2 = 0
OCD2 = 1
Divider
Oscillation
stop
detection
XIN clock
XOUT
CM13
CM05
XIN
CM02
WAIT
instruction
CM10 = 1 (stop mode)
a
d
c
h
b
CM06 = 0
CM17 to CM16 = 11b
CM06 = 1
CM06 = 0
CM17 to CM16 = 10b
CM06 = 0
CM17 to CM16 = 01b
CM06 = 0
CM17 to CM16 = 00b
Details of divider
Oscillation stop detection circuit
Pulse generation
circuit for clock edge
detection and
charge, discharge
control circuit
XIN clock
Forcible discharge when OCD0 = 0
Charge,
discharge
circuit
Oscillation stop detection
interrupt generation
circuit detection
Watchdog
timer interrupt
OCD1
OCD2 bit switch signal
CM14 bit switch signal
Oscillation stop
detection,
watchdog timer, voltage
monitor 2 interrupt
CM02, CM05, CM06: Bits in CM0 register
CM10, CM13, CM14, CM16, CM17: Bits in CM1 register
OCD0, OCD1, OCD2: Bits in OCD register
FRA00, FRA01: Bits in FRA0 register
e
g
UART0
A/D
converter
Timer RDTimer RBTimer RA
FRA2 register
fOCO
fOCO-S
INT0
SSU/IIC
Voltage watch
2 interrupt
Watchdog
timer
System clock
Low-speed
on-chip
oscillator
FRA1 register
Frequency adjustable
CM13
UART1
Divider
fOCO40M
On-chip oscillator
clock
Timer RE
High-speed
on-chip
oscillator
fOCO-F
Divider
(1/128)
fOCO128
Voltage
detection
circuit
RESET
Power-on reset
Software reset
Interrupt request

Renesas R8C/20 Specifications

General

Brand	Renesas
Model	R8C/20
Category	Control Unit
Language	English