Clock Generation Circuit - Renesas M16C/60 Series Hardware Manual

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M16C/6N5 Group

Clock Generation Circuit

The clock generation circuit contains four oscillator circuits as follows:
(1) Main clock oscillation circuit
(2) Sub clock oscillation circuit
(3) Ring oscillator
(4) PLL frequency synthesizer
Table 1.8.1 lists the clock generation circuit specifications. Figure 1.8.1 shows the clock generation circuit.
Figures 1.8.2 to 1.8.8 show the clock-related registers.
Table 1.8.1 Clock Generation Circuit Specifications
Item
oscillation circuit
Use of clock • CPU clock source
• Peripheral function
clock source
Clock frequency 0 to 16 MHz
Usable •Ceramic oscillator
oscillator •Crystal oscillator
Pins to connect X , X
IN
oscillator
Oscillation stop
Present
and re-oscillation
detection function
Oscillating
Oscillation status
after reset
Other
Externally derived clock can be input
Rev.1.00 2003.05.30 page 42
Main clock Sub clock
oscillation circuit
• CPU clock source
• Timer A, B's clock
source
32.768 kHz
•Crystal oscillator
X , X
OUT CIN COUT
Present
Stopped
Clock Generation Circuit
Ring oscillator
• CPU clock source
• CPU clock source
• Peripheral function
• Peripheral function
clock source
• CPU and peripheral clock source
function clock sources
when the main clock
stops oscillating
About 1 MHz 20 MHz
- -
- -
Present
Present
Stopped
Stopped
- -
PLL frequency
synthesizer