r5f21346mnfp Renesas Electronics Corporation., r5f21346mnfp Datasheet - Page 143

• Manufacturer Part Number: r5f21346mnfp
• Description: Single-chip Mcus Incorporates The R8c Cpu Core
• Manufacturer: Renesas Electronics Corporation.

R8C/34M Group
R01UH0131EJ0100 Rev.1.00
Jun 21, 2011
9.
The following five circuits are incorporated in the clock generation circuit:
• XIN clock oscillation circuit
• XCIN clock oscillation circuit
• Low-speed on-chip oscillator
• High-speed on-chip oscillator
• Low-speed on-chip oscillator for watchdog timer
9.1
Table 9.1
Notes:
Applications
Clock frequency 0 to 20 MHz
Connectable
oscillator
Oscillator
connect pins
Oscillation stop,
restart function
Oscillator status
after reset
Others
Table 9.1 lists the Specification Overview of Clock Generation Circuit. Figure 9.1 shows a Clock Generation
Circuit and Figure 9.2 shows a Peripheral Function Clock.
Clock Generation Circuit
1. These pins can be used as P4_6 and P4_7 when using the XCIN clock oscillation circuit or on-chip oscillator
2. These pins can be used as P4_3 and P4_4 when using the XIN clock oscillation circuit or on-chip oscillator
3. To input an external clock, set the CM05 bit in the CM0 register to 1 (XIN clock stops), the CM11 bit in the CM1
4. The clock frequency is automatically set to up to approx. 20 MHz by a divider when using the high-speed on-
5. This applies when the CSPROINI bit in the OFS register is set to 1 (count source protection mode disabled after reset).
6. This applies when the CSPROINI bit in the OFS register is set to 0 (count source protection mode enabled after reset).
Item
clock as the CPU clock while the XIN clock oscillation circuit is not used.
clock as the CPU clock while the XCIN clock oscillation circuit is not used.
register to 1 (internal feedback resistor disabled), and the CM13 bit to 1 (XIN-XOUT pin).
chip oscillator as the CPU clock source.
Overview
Specification Overview of Clock Generation Circuit
Oscillation Circuit
• CPU clock
• Peripheral
• Ceramic
• Crystal
XIN, XOUT
Usable
Stop
Externally
generated clock
can be input
source
function clock
source
resonator
oscillator
XIN Clock
(1)
(3)
• CPU clock
• Peripheral
32.768 kHz
• Crystal
XCIN, XCOUT
Usable
Stop
• Externally
• On-chip
Oscillation Circuit
source
function clock
source
oscillator
generated clock
can be input
feedback resistor
Rf (connected/
not connected
selectable)
XCIN Clock
(2)
On-Chip Oscillator
• CPU clock
• Peripheral
• CPU and
Approx. 40 MHz
−
−
Usable
Stop
−
source
function clock
source
peripheral function
clock source when
XIN clock stops
oscillating
(1)
High-Speed
On-Chip Oscillator
(4)
• CPU clock
• Peripheral
• CPU and
Approx. 125 kHz
−
−
Usable
Oscillate
−
On-Chip Oscillator
source
function clock
source
peripheral function
clock source when
XIN clock stops
oscillating
(1)
Low-Speed
9. Clock Generation Circuit
• Watchdog timer
Approx. 125 kHz
−
−
Usable
Stop
Oscillate
−
for Watchdog Timer
On-Chip Oscillator
clock source
Low-Speed
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