ATA6612C View Datasheet(PDF) - Atmel Corporation
Part Name
Description
MFG CO.
ATA6612C
Atmel Corporation
'ATA6612C' PDF : 312 Pages View PDF
5.7.1 Sleep Mode Control Register – SMCR
The sleep mode control register contains control bits for power management.
Bit
7
6
5
4
3
2
1
0
–
–
–
–
SM2
SM1
SM0
SE
SMCR
Read/Write
R
R
R
R
R/W
R/W
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
• Bits 7..4 Res: Reserved Bits
These bits are unused bits in the Atmel® ATA6612C/ATA6613C, 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 5-18.
Table 5-18. Sleep Mode Select
SM2
SM1
SM0
Sleep Mode
0
0
0
Idle
0
0
1
ADC noise reduction
0
1
0
Power-down
0
1
1
Power-save
1
0
0
Reserved
1
0
1
Reserved
1
1
0
Standby(1)
1
1
1
Reserved
Note: 1. Standby mode is only recommended for use with external crystals or resonators.
• 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.
5.7.2
Idle Mode
When the SM2..0 bits are written to 000, the SLEEP instruction makes the MCU enter idle mode, stopping the CPU but
allowing the SPI, USART, analog comparator, ADC, 2-wire serial interface, Timer/Counters, watchdog, and the interrupt
system to continue operating. This sleep mode basically halts clkCPU and clkFLASH, while allowing the other clocks to run.
Idle mode enables the MCU to wake up from external triggered interrupts as well as internal ones like the timer overflow and
USART transmit complete interrupts. If wake-up from the analog comparator interrupt is not required, the analog comparator
can be powered down by setting the ACD bit in the analog comparator control and status register – ACSR. This will reduce
power consumption in idle mode. If the ADC is enabled, a conversion starts automatically when this mode is entered.
5.7.3
ADC Noise Reduction Mode
When the SM2..0 bits are written to 001, the SLEEP instruction makes the MCU enter ADC noise reduction mode, stopping
the CPU but allowing the ADC, the external interrupts, the 2-wire serial interface address watch, Timer/Counter2, and the
watchdog to continue operating (if enabled). This sleep mode basically halts clkI/O, clkCPU, and clkFLASH, while allowing the
other clocks to run.
This improves the noise environment for the ADC, enabling higher resolution measurements. If the ADC is enabled, a
conversion starts automatically when this mode is entered. Apart from the ADC conversion complete interrupt, only an
external reset, a watchdog system reset, a watchdog interrupt, a brown-out reset, a 2-wire serial interface address match, a
Timer/Counter2 interrupt, an SPM/EEPROM ready interrupt, an external level interrupt on INT0 or INT1 or a pin change
interrupt can wake up the MCU from ADC noise reduction mode.
56 ATA6612C/ATA6613C [DATASHEET]
9111L–AUTO–11/14
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