Designed by Mark Little
The AT89C55WD has an important feature in that 1000 chips with associated 12 MHz crystals were being dumped at work, so after some "dumpster diving" and permission, they are now available for home projects, although no new projects have developed on this site - refer to the sites below for projects.
The AT89C55 is a low-power, high-performance CMOS 8-bit microcomputer with 20K bytes of Flash programmable and erasable read only memory and is compatible with the industry standard 80C51 instruction set and pinout.
The AT89C55WD provides the following standard features:
• 20K bytes of Flash,
• 256-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
the AT89C55 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. The low-voltage option saves power and operates with a 2.7-volt power supply.
AT89C55 Integrated Development Environment
This site uses the MCS-51 8051 IDE for developing the AT89C55 projects. Unlike the other projects, the AT89C55 currently require a programmer that runs using a Windows program to control the hardware.