The AT89S8253-24PU is a 8-bit low-power high-performance CMOS Microcontroller with 12kB of In-System Programmable (ISP) flash program memory and 2kB of EEPROM data memory. The device is manufactured using high-density non-volatile memory technology and is compatible with the industry-standard MCS-51 instruction set and pinout. The on-chip downloadable flash allows the program memory to be reprogrammed in-system through an SPI serial interface or by a conventional non-volatile memory programmer. By combining a versatile 8-bit CPU with downloadable flash on a monolithic chip, the AT89S8253 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications.