Renesas 7542 Manual page 63

7542 Group
X
On-chip oscillator mode
On-chip oscillator
Q S
R
Interrupt disable flag l
Interrupt request
Fig. 79 Block diagram of internal clock generating circuit (for ceramic resonator)
X
OUT
RING
On-chip oscillator
Q S
R
Interrupt disable flag l
Interrupt request
Fig. 80 Block diagram of internal clock generating circuit (for RC oscillation)
Rev.3.02 Oct 31, 2006
REJ03B0006-0302
X
IN OUT
(Note)
Clock division ratio selection bits
Middle-, high-, double-speed mode
1/2
1/2 1/16
1/4
STP instruction
Reset
Note: Although a feed-back resistor exists on-chip, an external feed-back resistor
may be needed depending on conditions.
X
IN
Clock division ratio selection bits
Middle-, high-, double-speed mode
On-chip
oscillator
mode
Delay
1/2
1/4
STP instruction
Reset
Page 63 of 134
Prescaler 1
1/2
1/4
Clock division
ratio selection bits
Middle-speed mode
High-speed mode
Double-speed mode
On-chip oscillator division
R /128
OSC
ratio selection bits
R /8
OSC
On-chip oscillator
R /2
OSC
mode
R /1
OSC
Q
S
WIT
R
instruction
1/2 1/4 1/2
High-speed mode
Double-speed mode
On-chip oscillator division
1/16
ratio selection bits
R /128
OSC
R /8
OSC
On-chip oscillator
mode
R /2
OSC
R /1
OSC
Q
S
WIT
R
instruction
Timer 1
Timing φ
(Internal
clock)
S
Q
RESET
R STP instruction
Timer 1
Prescaler 1
Clock division
ratio selection bits
Middle-speed mode
Timing φ
(Internal clock)
S
Q
R
STP instruction
RESET