R5F21238DFP#U0 Renesas Electronics America, R5F21238DFP#U0 Datasheet - Page 102

• Manufacturer Part Number: R5F21238DFP#U0
• Description: IC R8C/23 MCU FLASH 48-LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/2x/23r

Specifications of R5F21238DFP#U0

• Core Size: 16/32-Bit
• Program Memory Size: 64KB (64K x 8)
• Peripherals: POR, Voltage Detect, WDT
• Core Processor: R8C
• Speed: 20MHz
• Connectivity: CAN, I²C, LIN, SIO, SSU, UART/USART
• Number Of I /o: 41
• Program Memory Type: FLASH
• Ram Size: 3K x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 12x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 48-LQFP
• No. Of I/o's: 41
• Ram Memory Size: 3KB
• Cpu Speed: 20MHz
• No. Of Timers: 4
• Digital Ic Case Style: LQFP
• Embedded Interface Type: CAN, I2C, UART
• Rohs Compliant: Yes
• Cpu Family: R8C
• Device Core Size: 16b
• Frequency (max): 20MHz
• Interface Type: I2C/UART
• Total Internal Ram Size: 3KB
• # I/os (max): 41
• Number Of Timers - General Purpose: 5
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 3V
• On-chip Adc: 12-chx10-bit
• Instruction Set Architecture: CISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 48
• Package Type: LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With: RCDK8C - KIT DEV EVAL FOR CAN R8C/23R0K521237S000BE - KIT DEV RSK R8C/23R0E521237CPE00 - EMULATOR COMPACT R8C/20/21/22/23
• Eeprom Size: -
• Lead Free Status / Rohs Status: Compliant

R8C/22 Group, R8C/23 Group
Rev.2.00 Aug 20, 2008
REJ09B0251-0200
10.2
10.2.1
10.2.2
This clock is supplied by an on-chip oscillator. The on-chip oscillator contains a high-speed on-chip oscillator and
a low-speed on-chip oscillator. Either an on-chip oscillator clock is selected by the FRA01 bit in the FRA0 register.
The clock generated by the low-speed on-chip oscillator is used as the clock source for the CPU clock,
peripheral function clock, fOCO, and fOCO-S.
After reset, the on-chip oscillator clock generated by the low-speed on-chip oscillator by divide-by-8 is
selected for the CPU clock.
If the XIN clock stops oscillating when the OCD1 to OCD0 bits in the OCD register are set to 11b, the low-
speed on-chip oscillator automatically starts operating, supplying the necessary clock for the MCU.
The frequency of the low-speed on-chip oscillator varies depending on the supply voltage and the operating
ambient temperature. The application products must be designed with sufficient margin to accommodate the
frequency range.
The clock generated by the high-speed on-chip oscillator is used as the clock source for the CPU clock,
peripheral function clock, fOCO, fOCO-F and fOCO40M.
To use the high-speed on-chip oscillator clock as the clock source of the CPU clock, peripheral clock, fOCO,
and fOCO-F, set bits FRA20 to FRA22 in the FRA2 register as follows;
All divide ratio mode settings are supported when VCC = 3.0 V to 5.5 V (D, J version)000b to 111b
Divide ratio of 4 or more when VCC = 2.7 V to 5.5 V and K version
After reset, the on-chip oscillator clock generated by the high-speed on-chip oscillator stops. The oscillation
starts by setting the FRA00 bit in the FRA0 register to 1 (high-speed on-chip oscillator on). The frequency can
be adjusted by the FRA1 and FRA2 registers.
Since there are differences in the amount of frequency adjustment among the bits in the FRA1 register, make
adjustments by changing the settings of individual bits.
Adjust the amount of high-speed on-chip oscillator frequency to 40 MHz and below by setting the FRA1
register.
On-Chip Oscillator Clocks
Low-Speed On-Chip Oscillator Clock
High-Speed On-Chip Oscillator Clock
Page 80 of 501
10. Clock Generation Circuit
010b to 111b