AT  -  Series DataSheet
AT89C4051  -  8-bit Microcontroller with 4K Bytes Flash  -  Atmel  -  8051

Features
•Compatible with MCS®51 Products
•4K Bytes of Reprogrammable Flash Memory
– Endurance: 10,000 Write/Erase Cycles
•2.7V to 6V Operating Range
•Fully Static Operation: 0 Hz to 24 MHz
•Two-level Program Memory Lock
•128 x 8-bit Internal RAM
•15 Programmable I/O Lines
•Two 16-bit Timer/Counters
•Six Interrupt Sources
•Programmable Serial UART Channel
•Direct LED Drive Outputs
•On-chip Analog Comparator
•Low-power Idle and Power-down Modes
•Brown-out Detection
•Power-On Reset (POR)
•Green (Pb/Halide-free/RoHS Compliant) Packaging
Description
The AT89C4051 is a low-voltage, high-performance CMOS 8-bit microcontroller with 4K bytes of Flash programmable and erasable read-only memory. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C4051 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.
The AT89C4051 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five-vector, two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C4051 is designed with static logic for operation down to zero frequency and supports two software-selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset.