R5F21334CNFP#U0 Renesas Electronics America, R5F21334CNFP#U0 Datasheet - Page 560

• Manufacturer Part Number: R5F21334CNFP#U0
• Description: MCU 1KB FLASH 16K ROM 32-LQFP
• Manufacturer: Renesas Electronics America
• Series: R8C/3x/33Cr

Specifications of R5F21334CNFP#U0

• Core Processor: R8C
• Core Size: 16/32-Bit
• Speed: 20MHz
• Connectivity: I²C, LIN, SIO, SSU, UART/USART
• Peripherals: POR, PWM, Voltage Detect, WDT
• Number Of I /o: 27
• Program Memory Size: 16KB (16K x 8)
• Program Memory Type: FLASH
• Ram Size: 1.5K x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 12x10b; D/A 2x8b
• Oscillator Type: Internal
• Operating Temperature: -20°C ~ 85°C
• Package / Case: 32-LQFP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

R8C/33C Group
REJ09B0570-0100 Rev.1.00 Dec. 14, 2009
Page 530 of 589
Figure 31.2
31.2.10 Stopping Flash Memory
Notes:
FMR01, FMSTP: Bits in FMR0 register
2. Before switching the CPU clock source, make sure the designated
3. Insert a 60- µ s wait time by a program.
1. After setting the FMR01 bit to 1 (CPU rewrite mode enabled),
In low-speed on-chip oscillator mode and low-speed clock mode, power consumption can be further reduced by
stopping the flash memory using the FMSTP bit in the FMR0 register.
Access to the flash memory is disabled by setting the FMSTP bit to 1 (flash memory stops). The FMSTP bit
must be written to by a program transferred to RAM.
When the MCU enters stop mode or wait mode while CPU rewrite mode is disabled, the power for the flash
memory is automatically turned off. It is turned back on again after the MCU exit stop mode or wait mode. This
eliminates the need to set the FMR0 register.
Figure 31.2 shows the Handling Procedure Example for Reducing Power Consumption Using FMSTP Bit.
clock is stable.
Do not access the flash memory during this wait time.
set the FMSTP bit to 1 (flash memory stops).
Transfer the FMSTP bit setting program to
the RAM
Jump to the FMSTP bit setting program
(The subsequent processing is executed
by the program in the RAM)
Handling Procedure Example for Reducing Power Consumption Using FMSTP Bit
FMSTP bit setting program
Jump to the specified address in the flash memory
Write 1 to the FMSTP bit (flash memory stops.
low power consumption state)
After writing 0 to the FMR01 bit,
write 1 (CPU rewrite mode enabled)
Enter low-speed clock mode or
low-speed on-chip oscillator mode
Stop the high-speed on-chip oscillator
Write 0 to the FMSTP bit
(flash memory operates)
Write 0 to the FMR01 bit
(CPU rewrite mode disabled)
Wait until the flash memory circuit stabilizes
(60 µ s)
Switch the clock source for the CPU clock
Process in low-speed clock mode or
low-speed on-chip oscillator mode
(3)
31. Reducing Power Consumption
(1)
(2)