Chapter 6. Clock Generating Circuit; Clock Generation Circuit - Renesas M16C FAMILY Hardware Manual

Under development
Preliminary specification
Specifications in this manual are tentative and subject to change.
R8C/11 Group

6. Clock Generation Circuit

The clock generation circuit contains two oscillator circuits as follows:
• Main clock oscillation circuit
• Ring oscillator (oscillation stop detect function)
Table 6.1 lists the clock generation circuit specifications. Figure 6.1 shows the clock generation circuit.
Figures 6.2 and 6.4 show the clock-related registers.
Table 6.1 Clock Generation Circuit Specifications
Item
• CPU clock source
Use of clock
• Peripheral function
clock source
Clock frequency 0 to 20 MHz
• Ceramic oscillator
Usable oscillator
• Crystal oscillator
Pins to connect X
IN
oscillator
Present
Oscillation stop,
restart function
Stopped
Oscillator status
after reset
Externally derived
Other
clock can be input
Notes:
1. Can be used as P4
circuit is not used.
Rev.0.91 2003 Sep 08
Main clock
oscillation circuit
OUT 1
, X
and P4 when the ring oscillator clock is used for CPU clock while the main clock oscillation
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High-speed ring oscillator
• CPU clock source
• Peripheral function clock source
• CPU and peripheral function
clock sources when the main
clock stops oscillating
Approx. 8 MHz
1
Note
Present
Stopped
6. Clock Generating Circuit
Ring oscillator
Low-speed ring oscillator
• CPU clock source
• Peripheral function clock source
• CPU and peripheral function
clock sources when the main
clock stops oscillating
Approx. 125 kHz
1
Note
Present
Oscillating