Overview
The ATmega48P/88P/168P/328P 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 ATmega48P/88P/168P/328P achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed.
The AVR core combines a rich instruction set with 32 general purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers.

FEATUREs
• High Performance, Low Power AVR® 8-Bit Microcontroller
• Advanced RISC Architecture
   – 131 Powerful Instructions – Most Single Clock Cycle Execution
   – 32 x 8 General Purpose Working Registers
   – Fully Static Operation
   – Up to 20 MIPS Throughput at 20 MHz
   – On-chip 2-cycle Multiplier
• High Endurance Non-volatile Memory Segments
   – 4/8/16/32K Bytes of In-System Self-Programmable Flash progam memory (ATmega48P/88P/168P/328P)
   – 256/512/512/1K Bytes EEPROM (ATmega48P/88P/168P/328P)
   – 512/1K/1K/2K Bytes Internal SRAM (ATmega48P/88P/168P/328P)
   – Write/Erase Cycles: 10,000 Flash/100,000 EEPROM
– Data retention: 20 years at 85°C/100 years at 25°C(1)
   – Optional Boot Code Section with Independent Lock Bits
      In-System Programming by On-chip Boot Program
      True Read-While-Write Operation
   – Programming Lock for Software Security
• Peripheral Features
   – Two 8-bit Timer/Counters with Separate Prescaler and Compare Mode
   – 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 in TQFP and QFN/MLF package Temperature Measurement
   – 6-channel 10-bit ADC in PDIP Package Temperature Measurement
   – Programmable Serial USART
   – Master/Slave SPI Serial Interface
   – Byte-oriented 2-wire Serial Interface (Philips I2C compatible)
   – 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 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
   – 23 Programmable I/O Lines
   – 28-pin PDIP, 32-lead TQFP, 28-pad QFN/MLF and 32-pad QFN/MLF
• Operating Voltage:
   – 1.8 - 5.5V for ATmega48P/88P/168PV
   – 2.7 - 5.5V for ATmega48P/88P/168P
   – 1.8 - 5.5V for ATmega328P
• Temperature Range:
   – -40°C to 85°C
• Speed Grade:
   – ATmega48P/88P/168PV: 0 - 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V
   – ATmega48P/88P/168P: 0 - 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V
   – ATmega328P: 0 - 4 MHz @ 1.8 - 5.5V, 0 - 10 MHz @ 2.7 - 5.5V, 0 - 20 MHz @ 4.5 - 5.5V
• Low Power Consumption at 1 MHz, 1.8V, 25°C for ATmega48P/88P/168P:
   – Active Mode: 0.3 mA
   – Power-down Mode: 0.1 µA
   – Power-save Mode: 0.8 µA (Including 32 kHz RTC)