Rainbow Electronics ATmega128RFA1 - Manual (Page 167)

167
8266A-MCU Wireless-12/09
ATmega128RFA1
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 programmers 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.
12.6.2 PRR0 – Power Reduction Register0
Bit 7 6 5 4 3 2 1 0
NA ($64) PRTWI PRTIM2 PRTIM0 PRPGA PRTIM1 PRSPI PRUSART0 PRADC PRR0
Read/Write R/W R/W R/W R/W R/W R/W R/W R/W
Initial Value 0 0 0 0 0 0 0 0
• 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. 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 4 – PRPGA - Power Reduction PGA
Writing a logic one to this bit reduced the power consumption of the programmable gain
amplifier. The block is not turned off. Only the current levels in the amplifiers are
reduced. Reducing the PGA current levels is only recommended for slow ADC clock
frequencies. A new ADC conversion using the PGA should be delayed by a default
start-up time after changing (setting or resetting) this bit.
• 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 – PRUSART0 - Power Reduction USART
Writing a logic one to this bit shuts down the USART0 by stopping the clock to the
module. When waking up the USART0 again, the USART0 should be reinitialized 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 (reset
ADEN bit in register ADCSRA) before shut down. The analog comparator cannot use
the ADC input MUX when the ADC is shut down.