R5F21334CNFP#U0 Renesas Electronics America, R5F21334CNFP#U0 Datasheet - Page 558

• 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 528 of 589
31. Reducing Power Consumption
31.1
31.2
31.2.1
31.2.2
31.2.3
31.2.4
31.2.5
31.2.6
31.2.7
31.2.8
This chapter describes key points and processing methods for reducing power consumption.
Key points for reducing power consumption are shown below. They should be referred to when designing a system
or creating a program.
If voltage monitor 1 is not used, set the VCA26 bit in the VCA2 register to 0 (voltage detection 1 circuit
disabled). If voltage monitor 2 is not used, set the VCA27 bit in the VCA2 register to 0 (voltage detection 2
circuit disabled).
If the power-on reset and voltage monitor 0 reset are not used, set the VCA25 bit in the VCA2 register to 0
(voltage detection 0 circuit disabled).
Even after the MCU enters wait mode or stop mode, the states of the I/O ports are retained. Current flows into
the output ports in the active state, and shoot-through current flows into the input ports in the high-impedance
state. Unnecessary ports should be set to input and fixed to a stable electric potential before the MCU enters
wait mode or stop mode.
Power consumption generally depends on the number of the operating clocks and their frequencies. The fewer
the number of operating clocks or the lower their frequencies, the more power consumption decreases.
Unnecessary clocks should be stopped accordingly.
Stopping low-speed on-chip oscillator oscillation: CM14 bit in CM1 register
Stopping high-speed on-chip oscillator oscillation: FRA00 bit in FRA0 register
Power consumption can be reduced in wait mode and stop mode. Refer to 9.7 Power Control for details.
If the peripheral function f1, f2, f4, f8, and f32 clocks are not necessary in wait mode, set the CM02 bit in the
CM0 register to 1 (peripheral function clock stops in wait mode). This will stop the f1, f2, f4, f8, and f32 clocks
in wait mode.
If timer RA is not used, set the TCKCUT bit in the TRAMR register to 1 (count source cutoff).
If timer RB is not used, set the TCKCUT bit in the TRBMR register to 1 (count source cutoff).
If timer RC is not used, set the MSTTRC bit in the MSTCR register to 1 (standby).
When the A/D converter is not used, power consumption can be reduced by setting the ADSTBY bit in the
ADCON1 register to 0 (A/D operation stops (standby)) to shut off any analog circuit current flow.
When the SSU or the I
Overview
Key Points and Processing Methods for Reducing Power Consumption
Voltage Detection Circuit
Ports
Clocks
Wait Mode, Stop Mode
Stopping Peripheral Function Clocks
Timers
A/D Converter
Clock Synchronous Serial Interface
2
C bus is not used, set the MSTIIC bit in the MSTCR register to 1 (standby).
31. Reducing Power Consumption