Clock Generation Circuit - Renesas M16C FAMILY series Hardware Manual

M 1 6 C 2 / 8 G o r u p ( M 1 6 C

7. Clock Generation Circuit

The clock generation circuit contains four oscillator circuits as follows:
(1) Main clock oscillation circuit
(2) Sub clock oscillation circuit
(3) Variable on-chip oscillators
(4) PLL frequency synthesizer
Table 7.1 lists the clock generation circuit specifications. Figure 7.1 shows the clock generation circuit.
Figures 7.2 to 7.7 show the clock- associated registers.
Table 7.1 Clock Generation Circuit Specifications
Item
Oscillation Circuit
- CPU clock source
Use of clock
- Peripheral function
clock source
Clock frequency 0 to 20 MHz
- Ceramic oscillator
Usable oscillator
- Crystal oscillator
X , X
Pins to connect
IN
oscillator
Available
Oscillation stop,
restart function
Oscillating
Oscillator status
after reset
Externally derived clock can be input
Other
R e . v 2 0 . 0 J a . n 3 , 1 2 0 0 7
R E J 0 9 B 0 0 4 7 0 - 2 0 0
2 / , 8 M 1 6 C 2 / 8 ) B
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
Available
Stopped
page 44
f o 3 8 5
Variable On-chip Oscillator
- CPU clock source
- Peripheral function clock source
- CPU and peripheral function
clock sources when the main
clock stops oscillating
Selectable source frequency:
f , f , f
1(ROC) 2(ROC) 3(ROC)
Selectable divider:
by 2, by 4, by 8
Available
Oscillating
(CPU clock source)
7. Clock Generation Circuit
PLL Frequency
Synthesizer
- CPU clock source
- Peripheral function clock
source
10 to 20 MHz
Available
Stopped