Overview
The ATmega406 is a low-power CMOS 8-bit microcontroller based on the AVR enhanced RISC architecture. By executing powerful instructions in a single clock cycle, the ATmega406 achieves throughputs approaching 1 MIPS at 1 MHz.
   
Features
• High Performance, Low Power AVR® 8-bit Microcontroller
• Advanced RISC Architecture
    – 124 Powerful Instructions - Most Single Clock Cycle Execution
    – 32 x 8 General Purpose Working Registers
    – Fully Static Operation
    – Up to 1 MIPS Throughput at 1 MHz
• Nonvolatile Program and Data Memories
    – 40K Bytes of In-System Self-Programmable Flash, Endurance: 10,000 Write/Erase
        Cycles
    – Optional Boot Code Section with Independent Lock Bits
        In-System Programming by On-chip Boot Program
        True Read-While-Write Operation
    – 512 bytes EEPROM, Endurance: 100,000 Write/Erase Cycles
    – 2K Bytes Internal SRAM
    – Programming Lock for Software Security
• On-chip Debugging
    – Extensive On-chip Debug Support
    – Available through JTAG interface
• Battery Management Features
    – Two, Three, or Four Cells in Series
    – Deep Under-voltage Protection
    – Over-current Protection (Charge and Discharge)
    – Short-circuit Protection (Discharge)
    – Integrated Cell Balancing FETs
    – High Voltage Outputs to Drive Charge/Precharge/Discharge FETs
• Peripheral Features
    – One 8-bit Timer/Counter with Separate Prescaler, Compare Mode, and PWM
    – One 16-bit Timer/Counter with Separate Prescaler and Compare Mode
    – 12-bit Voltage ADC, Eight External and Two Internal ADC Inputs
    – High Resolution Coulomb Counter ADC for Current Measurements
    – TWI Serial Interface for SM-Bus
    – Programmable Wake-up Timer
    – Programmable Watchdog Timer
• Special Microcontroller Features
    – Power-on Reset
    – On-chip Voltage Regulator
    – External and Internal Interrupt Sources
    – Four Sleep Modes: Idle, Power-save, Power-down, and Power-off
• Packages
    – 48-pin LQFP
• Operating Voltage: 4.0 - 25V
• Maximum Withstand Voltage (High-voltage pins): 28V
• Temperature Range: -30°C to 85°C
    – Speed Grade: 1 MHz