Description: The AT89C51RC is a low-power, high-performance CMOS 8-bit microcontroller with 32K bytes of Flash programmable read-only memory and 512 bytes of RAM. The device is manufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard 80C51 and 80C52 instruction set and pinout. The on-chip Flash allows the program memory to be user programmed by a conventional nonvolatile memory programmer. A total of 512 bytes of internal RAM are available in the AT89C51RC. The 256-byte expanded internal RAM is accessed via MOVX instructions after clearing bit 1 in the SFR located at address 8EH. The other 256-byte RAM segment is accessed the same way as the Atmel AT89-series and other 8052-compatible products. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C51RC is a powerful microcomputer which pro- vides a highly-flexible and cost-effective solution to many embedded control applications.

The AT89C51RC provides the following standard features: 32K bytes of Flash, 512 bytes of RAM, 32 I/O lines, three 16-bit timer/counters, a six-vector two-level interrupt architecture, a full duplex serial port, on-chip oscillator, and clock circuitry. In addition, the AT89C51RC 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 con- tinue functioning. The Power-down mode saves the RAM contents but freezes the oscillator, disabling all other chip functions until the next external interrupt or hardware reset.