Description
The AT89S2051/S4051 is a low-voltage, high-performance CMOS 8-bit microcontrol ler with 2K/4K bytes of In-System Programmable (ISP) Flash program 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 AT89S2051/S4051 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. Moreover, the AT89S2051/S4051 is designed to be function compatible with the AT89C2051/C4051 devices, respectively.

FEATUREs
• Compatible with MCS® 51 Products
• 2K/4K Bytes of In-System Programmable (ISP) Flash Program Memory
– Serial Interface for Program Downloading
– Endurance: 10,000 Write/Erase Cycles
• 2.7V to 5.5V Operating Range
• Fully Static Operation: 0 Hz to 24 MHz
• Two-level Program Memory Lock
• 256 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 with Selectable Interrupt
• 8-bit PWM (Pulse-width Modulation)
• Low Power Idle and Power-down Modes
• Brownout Reset
• Enhanced UART Serial Port with Framing Error Detection and Automatic Address Recognition
• Internal Power-on Reset
• Interrupt Recovery from Power-down Mode
• Programmable and Fuseable x2 Clock Option
• Four-level Enhanced Interrupt Controller
• Power-off Flag
• Flexible Programming (Byte and Page Modes)
– Page Mode: 32 Bytes/Page
• User Serviceable Signature Page (32 Bytes)