ATMEGA328P-20PU Atmel, ATMEGA328P-20PU Datasheet - Page 44

• Manufacturer Part Number: ATMEGA328P-20PU
• Manufacturer: Atmel

Specifications of ATMEGA328P-20PU

• Cpu Family: ATmega
• Device Core: AVR
• Device Core Size: 8b
• Frequency (max): 20MHz
• Interface Type: SPI/TWI/USART
• Program Memory Type: Flash
• Program Memory Size: 32KB
• Total Internal Ram Size: 2KB
• # I/os (max): 23
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 3.3/5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 2.7V
• On-chip Adc: 6-chx10-bit
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Through Hole
• Pin Count: 28
• Package Type: PDIP
• Lead Free Status / Rohs Status: Compliant

9.11
9.11.1
9.11.2
8025K–AVR–10/09
Register Description
SMCR – Sleep Mode Control Register
MCUCR – MCU Control Register
The Sleep Mode Control Register contains control bits for power management.
• Bits 7..4 Res: Reserved Bits
These bits are unused bits in the ATmega48P/88P/168P, and will always read as zero.
• Bits 3..1 – SM2..0: Sleep Mode Select Bits 2, 1, and 0
These bits select between the five available sleep modes as shown in
Table 9-2.
Note:
• Bit 0 – SE: Sleep Enable
The SE bit must be written to logic one to make the MCU enter the sleep mode when the SLEEP
instruction is executed. To avoid the MCU entering the sleep mode unless it is the programmer’s
purpose, it is recommended to write the Sleep Enable (SE) bit to one just before the execution of
the SLEEP instruction and to clear it immediately after waking up.
• Bit 6 – BODS: BOD Sleep
The BODS bit must be written to logic one in order to turn off BOD during sleep, see
on page
BODSE in MCUCR. To disable BOD in relevant sleep modes, both BODS and BODSE must first
Bit
0x33 (0x53)
Read/Write
Initial Value
Bit
0x35 (0x55)
Read/Write
Initial Value
SM2
0
0
0
0
1
1
1
1
1. Standby mode is only recommended for use with external crystals or resonators.
39. Writing to the BODS bit is controlled by a timed sequence and an enable bit,
Sleep Mode Select
R
7
–
0
R
7
–
0
SM1
0
0
1
1
0
0
1
1
BODS
R/W
6
0
R
6
–
0
BODSE
R/W
R
5
–
0
5
0
SM0
0
1
0
1
0
1
0
1
R
PUD
4
–
0
R/W
0
4
Sleep Mode
Idle
ADC Noise Reduction
Power-down
Power-save
Reserved
Reserved
Standby
External Standby
SM2
R/W
3
0
ATmega48P/88P/168P
(1)
R
3
–
0
SM1
R/W
2
0
(1)
R
2
–
0
SM0
R/W
Table
IVSEL
1
0
R/W
1
0
9-2.
R/W
SE
IVCE
R/W
0
0
0
0
Table 9-1
MCUCR
SMCR
44