R5F21257SNFP#U0 Renesas Electronics America, R5F21257SNFP#U0 Datasheet - Page 430

• 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 19.11
NOTES:
1. Set the FMR01 bit to 1 (CPU rewrite mode enabled) before setting the
2. Before switching to a different clock source for the CPU, make sure
3. Insert a 30 µs wait time in a program. Do not access to the flash
Transfer a high-speed on-chip oscillator mode, low-
speed on-chip oscillator mode (XIN clock stops), and
low-speed clock mode (XIN clock stops) program to
the RAM.
Jump to the high-speed on-chip oscillator mode, low-
speed on-chip oscillator mode (XIN clock stops), and
low-speed clock mode (XIN clock stops) program
which has been transferred to the RAM.
(The subsequent processing is executed by the
program in the RAM.)
FMSTP bit to 1.
the designated clock is stable.
memory during this wait time.
Feb 29, 2008
Low-Speed On-Chip Oscillator Mode (XIN Clock Stops) and Low-Speed Clock Mode
(XIN Clock Stops)
Process to Reduce Power Consumption in High-Speed On-Chip Oscillator Mode,
Page 411 of 485
High-speed on-chip oscillator mode,
low-speed on-chip oscillator mode
(XIN clock stops), and low-speed
clock mode (XIN clock stops)
program
Jump to a specified address in the flash memory
Turn XIN clock on → wait until oscillation
stabilizes → switch the clock source for CPU
clock
Switch the clock source for the CPU clock.
Turn XIN off
Wait until the flash memory circuit stabilizes
(30 µ s)
Write 1 to the FMSTP bit (flash memory stops.
Process in high-speed on-chip oscillator
mode, low-speed on-chip oscillator mode
(XIN clock stops), and low-speed clock
mode (XIN clock stops)
Write 0 to the FMR01 bit before writing 1
(2)
(3)
low power consumption mode)
(CPU rewrite mode enabled)
(CPU rewrite mode disabled)
Write 0 to the FMR01 bit
(flash memory operation)
Write 0 to the FMSTP bit
19. Flash Memory
(1)