The AT89C2051-24PU is a low voltage, high performance CMOS 8bit microcontroller in 20 pin DIP package. The device is manufactured using high density non volatile memory technology and is compatible with industry standard MCS-51 instruction set. It provides highly flexible and cost effective solution to many applications by combining versatile 8bit CPU with flash on monolithic chip. The AT89C2051-24PU has on-chip analogue comparator, on-chip oscillator, clock circuitry, low power idle and power down modes. This microcontroller is designed with static logic for operation down to zero frequency and supports two software selectable power saving modes. The power down mode saves RAM contents but freezes oscillator disabling all other chip functions until the next hardware reset.