R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 92

• Manufacturer Part Number: R5F21257SNFP#U0
• Description: IC R8C/25 MCU FLASH 52LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/25r

Specifications of R5F21257SNFP#U0

• Core Processor: R8C
• Core Size: 16/32-Bit
• Speed: 20MHz
• Connectivity: I²C, LIN, SIO, SSU, UART/USART
• Peripherals: POR, Voltage Detect, WDT
• Number Of I /o: 41
• Program Memory Size: 48KB (48K x 8)
• Program Memory Type: FLASH
• Ram Size: 2.5K x 8
• Voltage - Supply (vcc/vdd): 2.2 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 52-LQFP
• For Use With: R0K521256S000BE - KIT EVAL STARTER FOR R8C/25
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/24 Group, R8C/25 Group
Rev.3.00
REJ09B0244-0300
10. Clock Generation Circuit
The clock generation circuit has:
Table 10.1 lists the Specifications of Clock Generation Circuit. Figure 10.1 shows a Clock Generation Circuit. Figures
10.2 to 10.8 show clock associated registers. Figure 10.9 shows the Procedure for Enabling Reduced Internal Power
Consumption Using VCA20 bit.
Table 10.1
NOTES:
Applications
Clock frequency 0 to 20 MHz
Connectable
oscillator
Oscillator
connect pins
Oscillation stop,
restart function
Oscillator status
after reset
Others
• XIN clock oscillation circuit
• XCIN clock oscillation circuit
• Low-speed on-chip oscillator
• High-speed on-chip oscillator
1. These pins can be used as P4_6 or P4_7 when using the on-chip oscillator clock as the CPU clock while the
2. These pins can be used as P4_3 and P4_4 when using the XIN clock oscillation circuit and on-chip oscillator
3. Set the CM05 bit in the CM0 register to 1 (XIN clock stopped) and the CM13 bit in the CM1 register to 1 (XIN-
4. The clock frequency is automatically set to up to 20 MHz by a divider when using the high-speed on-chip
Item
XIN clock oscillation circuit is not used.
clock for a CPU clock while the XCIN clock oscillation circuit is not used.
XOUT pin) when an external clock is input.
oscillator as the CPU clock source.
Feb 29, 2008
Specifications of Clock Generation Circuit
• Peripheral function
• Ceramic resonator
• Crystal oscillator
XIN, XOUT
Usable
Stop
Externally
generated clock can
be input
• CPU clock source
Oscillation Circuit
clock source
XIN Clock
Page 73 of 485
(3)
(1)
• CPU clock source
• Timer RA and timer RE
• Crystal oscillator
XCIN, XCOUT
Usable
Stop
• Externally generated
• On-chip feedback
32.768 kHz
clock source
clock can be input
resistor Rf (connected/
not connected,
selectable)
XCIN Clock Oscillation
Circuit
(2)
• CPU clock source
• Peripheral function
• CPU and peripheral
Approx. 40 MHz
−
−
Usable
Stop
−
(1)
High-Speed On-Chip
clock source
function clock
sources when XIN
clock stops oscillating
Oscillator
On-Chip Oscillator
(4)
10. Clock Generation Circuit
• CPU clock source
• Peripheral function
• CPU and peripheral
Approx. 125 kHz
−
−
Usable
Oscillate
−
(1)
clock source
function clock
sources when XIN
clock stops oscillating
Low-Speed On-Chip
Oscillator