ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 37

• Manufacturer Part Number: ATmega406
• Manufacturer: Atmel Corporation

Specifications of ATmega406

• Flash (kbytes): 40 Kbytes
• Pin Count: 48
• Max. Operating Frequency: 1 MHz
• Cpu: 8-bit AVR
• # Of Touch Channels: 8
• Hardware Qtouch Acquisition: No
• Max I/o Pins: 18
• Ext Interrupts: 4
• Usb Speed: No
• Usb Interface: No
• Twi (i2c): 1
• Graphic Lcd: No
• Video Decoder: No
• Camera Interface: No
• Adc Channels: 11
• Adc Resolution (bits): 12
• Adc Speed (ksps): 1.9
• Resistive Touch Screen: No
• Temp. Sensor: Yes
• Crypto Engine: No
• Sram (kbytes): 2
• Eeprom (bytes): 512
• Self Program Memory: YES
• Dram Memory: No
• Nand Interface: No
• Picopower: No
• Temp. Range (deg C): -30 to 85
• I/o Supply Class: 4.0 to 25
• Operating Voltage (vcc): 4.0 to 25
• Fpu: No
• Mpu / Mmu: no / no
• Timers: 2
• Output Compare Channels: 3
• Pwm Channels: 2
• 32khz Rtc: Yes
• Calibrated Rc Oscillator: Yes

8.7
8.7.1
8.7.2
8.7.3
8.7.4
8.7.5
2548E–AVR–07/06
Minimizing Power Consumption
Watchdog Timer
Port Pins
On-chip Debug System
Battery Protection
Voltage ADC
There are several issues 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 operating. 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 the Watchdog Timer is not needed in the application, the module should be turned off. If the
Watchdog Timer is enabled, it will be enabled in all sleep modes except Power-off. The Watch-
dog Timer current consumption is significant only in Power-down mode. See
on page 43
When entering a sleep mode, all port pins should be configured to use minimum power. The
most important is then to ensure that no pins drive resistive loads. In sleep modes where both
the I/O clock (clk
be disabled. This ensures that no power is consumed by the input logic when not needed. In
some cases, the input logic is needed for detecting wake-up conditions, and it will then be
enabled. See
enabled. If the input buffer is enabled and the input signal is left floating or have an analog signal
level close to V
For analog input pins, the digital input buffer should be disabled at all times. An analog signal
level close to V
input buffers can be disabled by writing to the Digital Input Disable Register. Refer to
Digital Input Disable Register 0” on page 120
If the On-chip debug system is enabled by OCDEN Fuse and the chip enters sleep mode, the
main clock source is enabled, and hence, always consumes power. In the deeper sleep modes,
this will contribute significantly to the total current consumption.
If one of the Battery Protection features is not needed by the application, this feature should be
disabled, see
FET is switched off, the Short-Circuit Circuitry will automatically be stopped in order to minimize
power consumption. The current consumption in the Battery Protection circuitry is only signifi-
cant in Power-down mode.
If enabled, the V-ADC will consume power independent of sleep mode. To save power, the V-
ADC should be disabled when not used, and before entering Power-save or Power-down sleep
modes. See
116
for details on V-ADC operation.
for details on how to configure the Watchdog Timer.
”Voltage ADC – 10-channel General Purpose 12-bit Sigma-Delta ADC” on page
”Digital Input Enable and Sleep Modes” on page 64
”BPCR – Battery Protection Control Register” on page
REG
REG
I/O
/2, the input buffer will use excessive power.
) and the ADC clock (clk
/2 on an input pin can cause significant current even in active mode. Digital
ADC
for details.
) are stopped, the input buffers of the device will
for details on which pins are
128. When the Discharge
ATmega406
”Watchdog Timer”
”DIDR0 –
37