Overview
The ATtiny43U 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 ATtiny43U 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
   – 123 Powerful Instructions – Most Single Clock Cycle Execution
   – 32 x 8 General Purpose Working Registers
   – Fully Static Operation
• Non-volatile Program and Data Memories
   – 4K Bytes of In-System Programmable Program Memory Flash
   – 64 Bytes of In-System Programmable EEPROM
   – 256 Bytes of Internal SRAM
   – Write/Erase Cycles: 10,000 Flash/ 100,000 EEPROM
   – Data Retention: 20 years at 85°C/ 100 years at 25°C
   – Programming Lock for Software Security
• Peripheral Features
   – QTouch® Library Support for Capacitive Touch Sensing (8 Channels)
   – Two 8-bit Timer/Counters with two PWM Channels, Each
   – Programmable Watchdog Timer with Separate On-chip Oscillator
   – On-chip Analog Comparator
   – 10-bit ADC
      • 4 Single-ended Channels
   – Universal Serial Interface
   – Boost Converter
• Special Microcontroller Features
   – debugWIRE On-chip Debug System
   – In-System Programmable via SPI Port
   – External and Internal Interrupt Sources
   – Pin Change Interrupt on 16 Pins
   – Low Power Idle, ADC Noise Reduction and Power-down Modes
   – Enhanced Power-on Reset Circuit
   – Programmable Brown-out Detection Circuit
   – Internal Calibrated Oscillator
   – Temperature Sensor On-chip
• I/O and Packages
   – Available in 20-pin SOIC and 20-pin QFN/MLF
   – 16 Programmable I/O Lines
• Operating Voltage:
   – 0.7 – 1.8V (via On-chip Boost Converter)
   – 1.8 – 5.5V (Boost Converter Bypassed)
• Speed Grade
   – Using On-chip Boost Converter
      • 0 – 4 MHz
   – External Power Supply
      • 0 – 4 MHz @ 1.8 – 5.5V
      • 0 – 8 MHz @ 2.7 – 5.5V
• Low Power Consumption
   – Active Mode, 1 MHz System Clock
      • 400 µA @ 3V (Without Boost Converter)
   – Power-down Mode
      • 150 nA @ 3V (Without Boost Converter)