ATmega8U2/16U2/32U2
9.10.2
PRR0 – Power Reduction Register 0
Bit
7
-
6
-
5
PRTIM0
R/W
0
4
–
3
PRTIM1
R/W
0
2
PRSPI
R/W
0
1
-
0
-
(0x64)
PRR0
Read/Write
Initial Value
R/W
0
R/W
0
R
0
R
0
R/W
0
• Bit 7:6 - Res: Reserved bits
These bits are reserved and will always read as zero.
• Bit 5 - PRTIM0: Power Reduction Timer/Counter0
Writing a logic one to this bit shuts down the Timer/Counter0 module. When the Timer/Counter0
is enabled, operation will continue like before the shutdown.
• Bit 4 - Res: Reserved bit
This bit is reserved and will always read as zero.
• Bit 3 - PRTIM1: Power Reduction Timer/Counter1
Writing a logic one to this bit shuts down the Timer/Counter1 module. When the Timer/Counter1
is enabled, operation will continue like before the shutdown.
• Bit 2 - PRSPI: Power Reduction Serial Peripheral Interface
Writing a logic one to this bit shuts down the Serial Peripheral Interface by stopping the clock to
the module. When waking up the SPI again, the SPI should be re initialized to ensure proper
operation.
• Bit 1 - Res: Reserved bit
These bits are reserved and will always read as zero.
• Bit 0 - Res: Reserved bit
These bits are reserved and will always read as zero.
9.10.3
PRR1 – Power Reduction Register 1
Bit
(0x65)
7
6
–
5
–
4
–
3
-
2
–
1
–
0
PRUSB
PRUSART1
PRR1
Read/Write
Initial Value
R/W
0
R
0
R
0
R
0
R/W
0
R
0
R
0
R/W
0
• Bit 7 - PRUSB: Power Reduction USB
Writing a logic one to this bit shuts down the USB by stopping the clock to the module. When
waking up the USB again, the USB should be re initialized to ensure proper operation.
• Bit 6:1 - Res: Reserved bits
These bits are reserved and will always read as zero.
• Bit 0 - PRUSART1: Power Reduction USART1
Writing a logic one to this bit shuts down the USART1 by stopping the clock to the module.
When waking up the USART1 again, the USART1 should be re initialized to ensure proper
operation.
46
7799D–AVR–11/10
ATMEL [ ATMEL ]
