ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 26

• 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

7.1.5
7.1.6
7.1.7
7.2
7.3
26
Clock Sources
Calibrated Fast RC Oscillator
ATmega406
Voltage ADC Clock – clk
Coulomb Counter ADC Clock - clk
Watchdog Timer and Battery Protection Clock
The Voltage ADC is provided with a dedicated clock domain. This allows halting the CPU and
I/O clocks in order to reduce noise generated by digital circuitry. This gives more accurate ADC
conversion results.
The Coulomb Counter ADC is provided with a dedicated clock domain. This allows operating the
Coulomb Counter ADC in low power modes like Power-save for continuous current
measurements.
The Watchdog Timer and Battery Protection are provided with a dedicated clock domain. This
allows operation in all modes except Power-off. It also allows very low power operation by utiliz-
ing an Ultra Low Power RC Oscillator dedicated to this purpose.
The device has the following clock sources. The clocks are input to the AVR clock generator,
and routed to the appropriate modules.
The calibrated Fast RC Oscillator by default provides a 4.0 MHz clock, which is divided down to
1.0 MHz to all modules except the TWI. The frequency is nominal value at 25°C. This clock will
operate with no external components. During reset, hardware loads the calibration byte into the
FOSCCAL Register and thereby automatically calibrates the Fast RC Oscillator. At 25°C, this
calibration gives a frequency of 4 MHz ± 3%. The oscillator can be calibrated to any frequency in
the range 3.7 - 4.0 MHz within ±1% accuracy, by changing the FOSCCAL register. For more
information on the pre-programmed calibration value, see the section
page
The start-up times for the Fast RC Oscillator are determined by the SUT Fuses as shown in
Table 7-1 on page
Table 7-1.
Note:
198.
SUT1:0
1. The device is shipped with this option selected.
VADC
00
01
10
11
Start-up times for the internal calibrated RC Oscillator clock selection
26.
CCADC
Start-up Time from Power-down
and Power-save
6 CK
6 CK
6 CK
Reserved
Additional Delay from Reset
14CK + 65 ms
14CK + 4.1 ms
”Calibration Bytes” on
14CK
2548E–AVR–07/06
(1)