AT89C52 8-bit 8051 microcontroller — 8KB Flash, 256B RAM, DIP-40

The AT89C52 is a low-power, high-performance CMOS 8-bit microcontroller from Atmel (now Microchip), belonging to the classic MCS-51 / 8051 family. It features 8KB of in-system reprogrammable Flash memory, making it a cost-effective and flexible solution for embedded control applications. Fully compatible with the industry-standard 80C51 and 80C52 instruction set and pinout, it is widely used in academic projects, industrial control, and legacy embedded systems.

Key Specifications:

• Architecture: 8-bit MCS-51 (8051 compatible)
• Program memory: 8KB Flash (PEROM), 1000 write/erase cycles endurance
• Data memory (RAM): 256 bytes on-chip
• I/O ports: 4 × 8-bit bidirectional ports (32 I/O pins total)
• Timers/Counters: 3 × 16-bit (Timer 0, 1, 2)
• Serial interface: full-duplex UART
• Interrupts: 6 interrupt sources (2 external, 3 timer, 1 serial)
• Operating frequency: 0 – 24 MHz
• Operating voltage: 4.0V – 5.5V
• Power-down and idle modes for low-power operation
• Watchdog timer
• Package: DIP-40 (through-hole)
• Pb-free / RoHS compliant

Pinout Highlights (DIP-40):

• P0 (pins 32–39): Port 0 — 8-bit bidirectional I/O / address bus (AD0–AD7)
• P1 (pins 1–8): Port 1 — 8-bit bidirectional I/O with T2/T2EX on P1.0/P1.1
• P2 (pins 21–28): Port 2 — 8-bit bidirectional I/O / high address bus (A8–A15)
• P3 (pins 10–17): Port 3 — 8-bit bidirectional I/O with alternate functions (RXD, TXD, INT0, INT1, T0, T1, WR, RD)
• Pin 9: RST (reset, active high)
• Pin 18–19: XTAL1/XTAL2 (crystal oscillator)
• Pin 20: GND, Pin 40: VCC
• Pin 29: PSEN, Pin 30: ALE/PROG, Pin 31: EA/VPP

Compatible With:

• Keil µVision (C51 compiler)
• SDCC (Small Device C Compiler)
• 8051 development boards and minimum system boards
• Standard 8051 programmers (e.g. TL866, RT809H with 8051 adapter)
• Proteus simulation software

Applications:

• Academic and university embedded systems projects
• Industrial automation and control
• Home automation and relay control
• LCD and keypad interface projects
• Serial communication systems
• Legacy 8051-based product development