The document introduces the features and characteristics of AT89C4051, including compatibility, storage capacity, operating voltage range, operating frequency, program memory lock, internal RAM, programmable I/O lines, two 16-bit timers/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), etc.
The AT89C4051 is a low‑voltage, high‑performance 8‑bit CMOS microcontroller with 4 KB of flash memory, 128 bytes of RAM and 15 programmable I/O lines. It is compatible with the MCS‑51 instruction set and operates from 2.7 V to 6 V with a CPU frequency up to 24 MHz.
This manual covers the pin configuration for PDIP and SOIC packages, detailed pin descriptions, oscillator options, special function registers, programming procedures, power‑saving modes, lock‑bit protection, and package dimensions. It also includes usage notes for idle, power‑down, and brown‑out detection features.
| Flash Memory | 4 KB |
|---|---|
| Internal RAM | 128 bytes (8‑bit ×128) |
| Programmable I/O Lines | 15 |
| Timer/Counters | Two 16‑bit timers |
| Interrupt Sources | Six |
| Serial Interface | Programmable UART channel |
| Analog Comparator | On‑chip |
| Operating Voltage | 2.7 V to 6 V |
| Maximum CPU Frequency | 24 MHz |
The AT89C4051 contains 4 KB of reprogrammable flash memory.
It provides 15 programmable I/O lines.
The device operates from 2.7 V up to 6 V.
The CPU can run up to 24 MHz.