Overview
The ATmega164P/324P/644P 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 ATmega164P/324P/644P achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.

FEATUREs
• High-performance, Low-power AVR® 8-bit Microcontroller
• Advanced RISC Architecture
   – 131 Powerful Instructions – Most Single-clock Cycle Execution
   – 32 × 8 General Purpose Working Registers
   – Fully Static Operation
   – Up to 16 MIPS Throughput at 16 MHz
   – On-chip 2-cycle Multiplier
• Nonvolatile Program and Data Memories
   – 16/32/64K 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
   – 512B/1K/2K Bytes EEPROM
      Endurance: 100,000 Write/Erase Cycles
   – 1/2/4K Bytes Internal SRAM
   – Programming Lock for Software Security
• JTAG (IEEE std. 1149.1 Compliant) Interface
   – Boundary-scan Capabilities According to the JTAG Standard
   – Extensive On-chip Debug Support
   – Programming of Flash, EEPROM, Fuses, and Lock Bits through the JTAG Interface
• Peripheral Features
   – Two 8-bit Timer/Counters with Separate Prescalers and Compare Modes
   – One 16-bit Timer/Counter with Separate Prescaler, Compare Mode, and Capture Mode
   – Real Time Counter with Separate Oscillator
   – Six PWM Channels
   – 8-channel, 10-bit ADC Differential mode with selectable gain at 1x, 10x or 200x(1)
   – Byte-oriented Two-wire Serial Interface
   – Two Programmable Serial USART
   – Master/Slave SPI Serial Interface
   – Programmable Watchdog Timer with Separate On-chip Oscillator
   – On-chip Analog Comparator
   – Interrupt and Wake-up on Pin Change
• Special Microcontroller Features
   – Power-on Reset and Programmable Brown-out Detection
   – Internal Calibrated RC Oscillator
   – External and Internal Interrupt Sources
   – Six Sleep Modes: Idle, ADC Noise Reduction, Power-save, Power-down, Standby and Extended Standby
• I/O and Packages
   – 32 Programmable I/O Lines
   – 44-lead TQFP, and 44-pad QFN/MLF
• Operating Voltages
   – 2.7 - 5.5V for ATmega164P/324P/644P
• Speed Grades
   – ATmega164P/324P/644P: 0 - 8MHz @ 2.7 - 5.5V, 0 - 16MHz @ 4.5 - 5.5V
• Power Consumption at 8 MHz, 5V, 25°C for ATmega644P
   – Active mode: 8 mA
   – Idle mode: 2.4 mA
   – Power-down Mode: 0.8 µA