R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 104

• 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
10.4
10.4.1
10.4.2
10.4.3
10.4.4
10.4.5
10.4.6
10.4.7
10.4.8
There are a CPU clock to operate the CPU and a peripheral function clock to operate the peripheral functions. Refer
to Figure 10.1 Clock Generation Circuit.
The system clock is the clock source for the CPU and peripheral function clocks. Either the XIN clock or the
on-chip oscillator clock can be selected.
The CPU clock is an operating clock for the CPU and watchdog timer.
When the CM07 bit in the CM0 register is set to 0 (system clock), the system clock can be divided by 1 (no
division), 2, 4, 8, or 16 to produce the CPU clock. Use the CM06 bit in the CM0 register and bits CM16 to
CM17 in the CM1 register to select the value of the division.
When the CM07 bit in the CM0 register is set to 1 (XCIN clock), the XCIN clock is used for the CPU clock.
Use the XCIN clock while the XCIN clock oscillation stabilizes.
After reset, the low-speed on-chip oscillator clock divided by 8 provides the CPU clock.
When entering stop mode from high-speed clock mode, the CM06 bit is set to 1 (divide-by-8 mode).
The peripheral function clock is the operating clock for the peripheral functions.
The clock fi (i = 1, 2, 4, 8, and 32) is generated by the system clock divided by i. The clock fi is used for timers
RA, RB, RD, and RE, the serial interface and the A/D converter.
When the WAIT instruction is executed after setting the CM02 bit in the CM0 register to 1 (peripheral function
clock stops in wait mode), the clock fi stop.
fOCO is an operating clock for the peripheral functions.
fOCO runs at the same frequency as the on-chip oscillator clock and can be used as the source for timer RA.
When the WAIT instruction is executed, the clocks fOCO does not stop.
fOCO40M is used as the count source for timer RD. fOCO40M is generated by the high-speed on-chip
oscillator and supplied by setting the FRA00 bit to 1.
When the WAIT instruction is executed, the clock fOCO40M does not stop.
fOCO40M can be used with supply voltage VCC = 3.0 to 5.5 V.
fOCO-F is used as the count source for the A/D converter. fOCO-F is generated by the high-speed on-chip
oscillator and supplied by setting the FRA00 bit to 1.
When the WAIT instruction is executed, the clock fOCO-F does not stop.
fOCO-S is an operating clock for the watchdog timer and voltage detection circuit. fOCO-S is supplied by
setting the CM14 bit to 0 (low-speed on-chip oscillator on) and uses the clock generated by the low-speed on-
chip oscillator. When the WAIT instruction is executed or in count source protect mode of the watchdog timer,
fOCO-S does not stop.
fOCO128 is generated by fOCO divided by 128.
The clock fOCO128 is used for capture signal of timer RD (channel 0).
CPU Clock and Peripheral Function Clock
Feb 29, 2008
System Clock
CPU Clock
Peripheral Function Clock (f1, f2, f4, f8, and f32)
fOCO
fOCO40M
fOCO-F
fOCO-S
fOCO128
Page 85 of 485
10. Clock Generation Circuit