R8C/13 Group
6. Clock Generating Circuit
6. Clock Generation Circuit
The clock generation circuit contains two oscillator circuits as follows:
• Main clock oscillation circuit
• On-chip oscillator (with oscillation stop detection function)
Table 6.1 lists the clock generation circuit specifications. Figure 6.1 shows the clock generation circuit.
Figures 6.2 to 6.4 show the clock-related registers.
Table 6.1 Clock Generation Circuit Specifications
On-chip oscillator
Main clock
Item
oscillation circuit
High-speed on-chip oscillator
Low-speed on-chip oscillator
• CPU clock source
• Peripheral function
clock source
• CPU clock source
• CPU clock source
Use of clock
• Peripheral function clock source
• CPU and peripheral function
clock sources when the main
clock stops oscillating
• Peripheral function clock source
• CPU and peripheral function
clock sources when the main
clock stops oscillating
Clock frequency 0 to 20 MHz
Approx. 8 MHz
Approx. 125 kHz
• Ceramic resonator
• Crystal oscillator
Usable oscillator
(
X
IN, XOUT 1)
Pins to connect
oscillator
(Note 1)
(Note 1)
Present
Stopped
Present
Stopped
Oscillation starts
and stops
Present
Oscillator status
after reset
Oscillating
Externally derived
clock can be input
Other
NOTES:
1. Can be used as P4
circuit is not used.
6 and P47 when the on-chip oscillator clock is used for CPU clock while the main clock oscillation
Rev.1.20 Jan 27, 2006 page 29 of 205
REJ09B0111-0120
RENESAS [ RENESAS TECHNOLOGY CORP ]
