R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 97

• 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
Figure 10.5
High-Speed On-Chip Oscillator Control Register 0
High-Speed On-Chip Oscillator Control Register 1
b7 b6 b5 b4
NOTES:
b7 b6 b5 b4
NOTES:
0 0 0 0
1.
2.
3.
1.
2. When changing the values of the FRA1 register, adjust the FRA1 register so that the frequency of the high-speed
Set the PRC0 bit in the PRCR register to 1 (w rite enable) before rew riting the FRA0 register.
Change the FRA01 bit under the follow ing conditions.
• FRA00 = 1 (high-speed on-chip oscillation)
• The CM14 bit in the CM1 register = 0 (low -speed on-chip oscillator on)
• Bits FRA22 to FRA20 in the FRA2 register:
When setting the FRA01 bit to 0 (low -speed on-chip oscillator selected), do not set the FRA00 bit to 0 (high-speed
on-chip oscillator off) at the same time.
Set the FRA00 bit to 0 after setting the FRA01 bit to 0.
Set the PRC0 bit in the PRCR register to 1 (w rite enable) before rew riting the FRA1 register.
on-chip oscillator clock w ill be 40 MHz or less.
Feb 29, 2008
All divide ratio mode settings are supported w hen VCC = 3.0 V to 5.5 V 000b to 111b
Divide ratio of 4 or more w hen VCC = 2.7 V to 5.5 V
Divide ratio of 8 or more w hen VCC = 2.2 V to 5.5 V
b3 b2 b1 b0
0 0
b3 b2 b1 b0
Registers FRA0 and FRA1
The frequency of the high-speed on-chip oscillator is adjusted w ith bits 0 to 7.
High-speed on-chip oscillator frequency = 40 MHz (FRA1 register = value w hen shipping)
Setting the FRA1 register to a low er value results in a higher frequency.
Setting the FRA1 register to a higher value results in a low er frequency.
Bit Symbol
(b7-b2)
Symbol
FRA00
FRA01
Symbol
FRA0
FRA1
Page 78 of 485
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High-speed on-chip oscillator
enable bit
High-speed on-chip oscillator
select bit
Reserved bits
(2)
Address
Bit Name
0023h
Address
0024h
(1)
(1)
Function
0 : High-speed on-chip oscillator off
1 : High-speed on-chip oscillator on
0 : Selects low -speed on-chip oscillator
1 : Selects high-speed on-chip oscillator
Set to 0.
010b to 111b (divide by 4 or more)
110b to 111b (divide by 8 or more)
When Shipping
After Reset
After Reset
Function
00h
(2)
10. Clock Generation Circuit
(3)
RW
RW
RW
RW
RW
RW