15.11.3 Power Reduction Register

Name: PRR
Offset: 0x64
Reset: 0x00
Property: -

Bit 76543210 
 PRTWIPRTIM2PRTIM0 PRTIM1PRSPIPRUSARTPRADC 
Access R/WR/WR/WR/WR/WR/WR/W 
Reset 0000000 

Bit 7 – PRTWI Power Reduction TWI

Writing a logic one to this bit shuts down the TWI by stopping the clock to the module. When waking up the TWI again, the TWI should be re initialized to ensure proper operation.

Bit 6 – PRTIM2 Power Reduction Timer/Counter2

Writing a logic one to this bit shuts down the Timer/Counter2 module in synchronous mode (AS2 is 0). When the Timer/Counter2 is enabled, operation will continue like before the shutdown.

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 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

If using debugWIRE On-chip Debug System, this bit should not be written to one. 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 – PRUSART Power Reduction USART

Writing a logic one to this bit shuts down the USART by stopping the clock to the module. When waking up the USART again, the USART should be re initialized to ensure proper operation.

Bit 0 – PRADC Power Reduction ADC

Writing a logic one to this bit shuts down the ADC. The ADC must be disabled before shut down. The analog comparator cannot use the ADC input MUX when the ADC is shut down.