Atmel's AT89C4051 is low-voltage, high-performance CMOS 8-bit microcontroller with 4KB of flash programmable and erasable read-only memory (PEROM). The device uses Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. This versatile 8-bit CPU with flash provides a highly-flexible and cost-effective solution for many embedded control applications.

Features of AT89C4051 Microcontroller:-

• Flash (Kbytes):4 Kbytes
  
• Pin Count:20
  
• Max. Operating Freq. (MHz):24 MHz
  
• CPU:8051-12C
  
• Max I/O Pins:15
  
• UART:1
  
• SRAM (Kbytes): 0.125
  
• Operating Voltage (Vcc): 2.7 to 6.0
  
• Timers: 2