ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 42

• 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

9.2.3
9.2.4
42
ATmega406
Watchdog Reset
Brown-out Detection
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On
the falling edge of this pulse, the delay timer starts counting the Time-out period t
page 43
Figure 9-4.
ATmega406 has an On-chip Brown-out Detection (BOD) circuit for monitoring the VREG level
during operation by comparing it to a fixed trigger level V
teresis to ensure spike free Brown-out Detection. The hysteresis on the detection level should
be interpreted as V
The BOD is automatically enabled in all modes of operation, except in Power-off mode.
When the BOD is enabled, and VREG decreases to a value below the trigger level (V
ure
level (V
expired.
Figure 9-5.
9-5), the Brown-out Reset is immediately activated. When V
BOT+
INTERNAL
for details on operation of the Watchdog Timer.
TIME-OUT
RESET
RESET
VREG
in
FET
Watchdog Reset During Operation
Brown-out Reset During Operation
Figure
BOT+
9-5), the delay counter starts the MCU after the Time-out period t
= V
BOT
+ V
HYST
V
BOT-
/2 and V
CK
BOT-
= V
BOT
BOT
- V
= 2.7V. The trigger level has a hys-
HYST
V
t
CC
TOUT
BOT+
/2.
increases above the trigger
TOUT
2548E–AVR–07/06
BOT-
. Refer to
TOUT
in
Fig-
has