ATMEGA168PA-PU Atmel, ATMEGA168PA-PU Datasheet - Page 42

• Manufacturer Part Number: ATMEGA168PA-PU
• Description: MCU, 8BIT, AVR, 16K FLASH, 28PDIP
• Manufacturer: Atmel

Specifications of ATMEGA168PA-PU

• Controller Family/series: Atmega
• No. Of I/o's: 23
• Eeprom Memory Size: 512Byte
• Ram Memory Size: 1KB
• Cpu Speed: 20MHz
• No.: RoHS Compliant
• Core Size: 8bit
• Program Memory Size: 16KB
• Oscillator Type: External, Internal
• Rohs Compliant: Yes

9.8
9.9
9.10
9.10.1
9.10.2
9.10.3
8271C–AVR–08/10
Extended Standby Mode
Power Reduction Register
Minimizing Power Consumption
Analog to Digital Converter
Analog Comparator
Brown-out Detector
When the SM2...0 bits are 111 and an external crystal/resonator clock option is selected, the
SLEEP instruction makes the MCU enter Extended Standby mode. This mode is identical to
Power-save with the exception that the Oscillator is kept running. From Extended Standby
mode, the device wakes up in six clock cycles.
The Power Reduction Register (PRR), see
vides a method to stop the clock to individual peripherals to reduce power consumption. The
current state of the peripheral is frozen and the I/O registers can not be read or written.
Resources used by the peripheral when stopping the clock will remain occupied, hence the
peripheral should in most cases be disabled before stopping the clock. Waking up a module,
which is done by clearing the bit in PRR, puts the module in the same state as before shutdown.
Module shutdown can be used in Idle mode and Active mode to significantly reduce the overall
power consumption. In all other sleep modes, the clock is already stopped.
There are several possibilities to consider when trying to minimize the power consumption in an
AVR controlled system. In general, sleep modes should be used as much as possible, and the
sleep mode should be selected so that as few as possible of the device’s functions are operat-
ing. All functions not needed should be disabled. In particular, the following modules may need
special consideration when trying to achieve the lowest possible power consumption.
If enabled, the ADC will be enabled in all sleep modes. To save power, the ADC should be dis-
abled before entering any sleep mode. When the ADC is turned off and on again, the next
conversion will be an extended conversion. Refer to
for details on ADC operation.
When entering Idle mode, the Analog Comparator should be disabled if not used. When entering
ADC Noise Reduction mode, the Analog Comparator should be disabled. In other sleep modes,
the Analog Comparator is automatically disabled. However, if the Analog Comparator is set up
to use the Internal Voltage Reference as input, the Analog Comparator should be disabled in all
sleep modes. Otherwise, the Internal Voltage Reference will be enabled, independent of sleep
mode. Refer to
Comparator.
If the Brown-out Detector is not needed by the application, this module should be turned off. If
the Brown-out Detector is enabled by the BODLEVEL Fuses, it will be enabled in all sleep
modes, and hence, always consume power. In the deeper sleep modes, this will contribute sig-
nificantly to the total current consumption. Refer to
on how to configure the Brown-out Detector.
ATmega48A/48PA/88A/88PA/168A/168PA/328/328
”Analog Comparator” on page 247
”PRR – Power Reduction Register” on page
”Brown-out Detection” on page 49
for details on how to configure the Analog
”Analog-to-Digital Converter” on page 251
for details
45, pro-
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