ATmega406 Atmel Corporation, ATmega406 Datasheet - Page 125

• 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

22. Battery Protection
22.1
Table 22-1.
2548E–AVR–07/06
Battery Protection Type
Deep Under-voltage
Detected
Discharge Over-current
Protection
Charge Over-current
Protection
Short-circuit Protection
Features
Effect of Battery Protection Types
•
•
•
•
•
•
If the voltage at the VFET pin falls below the programmable Deep Under-voltage detection level,
C-FET, PC-FET, and D-FET are disabled and the chip is set in Power-off mode to reduce power
consumption to a minimum.
The Current Battery Protection circuitry (CBP) monitors the charge and discharge current and
disables C-FET, PC-FET, and D-FET if an over-current or short-circuit condition is detected.
There are three different programmable detection levels: Discharge Over-current Detection
Level, Charge Over-current Detection Level and Short-circuit Detection Level. The external filter
at the PI/NI input pins will cause too large delay for short-circuit detection. Therefore the sepa-
rate PPI/NNI inputs are used for Current Battery Protection. There are two different
programmable delays for activating Current Battery Protection: Short-circuit Reaction Time and
Over-current Reaction Time. After Current Battery Protection has been activated, the application
software must re-enable the FETs. The Battery Protection hardware provides a hold-off time of 1
second before software can re-enable the discharge FET. This provides safety in case the appli-
cation software should unintentionally re-enable the discharge FET too early.
The activation of a protection also issues an interrupt to the CPU. The battery protection inter-
rupts can be individually enabled and disabled by the CPU.
The effect of the various battery protection types is given in
In order to reduce power consumption, both Short-circuit and Discharge Over-current Protection
are automatically deactivated when the D-FET is disabled. The Charge Over-current Protection
is disabled when both the C-FET and the PC-FET are disabled. Note however that Charge Over-
current Protection is never automatically disabled when any of the C-FET or PC-FETs are con-
trolled by PWM.
Interrupt Requests
CPU Reset on exit
Entry and exit
Entry and exit
Entry and exit
Deep Under-voltage Protection
Charge Over-current Protection
Discharge Over-current Protection
Short-circuit Protection
Programmable and Lockable Detection Levels and Reaction Times
Autonomous Operation Independent of CPU
C-FET
Disabled
Disabled
Disabled
Disabled
D-FET
Disabled
Disabled
Disabled
Disabled
PC-FET
Disabled
Disabled
Disabled
Disabled
Cell Balancing FETs
Disabled
Operational
Operational
Operational
Table
22-1.
ATmega406
MCU
Power-off
Operational
Operational
Operational
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