The AT89LP2052/LP4052 is a low-power, high-performance CMOS 8-bit microcontroller with 2/4K bytes of In-System Programmable Flash memory. The device is manufactured using Atmel's high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. The AT89LP2052/LP4052 is built around an enhanced CPU core that can fetch a single byte from memory every clock cycle. In the classic 8051 architecture, each fetch required 6 clock cycles, forcing instructions to execute in 12, 24 or 48 clock cycles. In the AT89LP2052/LP4052 CPU, instructions need only 1 to 4 clock cycles providing 6 to 12 times more throughput than the standard 8051. Seventy percent of instructions need only as many clock cycles as they have bytes to execute, and most of the remaining instructions require only one additional clock. The enhanced CPU core is capable of 20 MIPS throughput whereas the classic 8051 CPU can deliver only 4 MIPS at the same current consumption. Conversely, at the same throughput as the classic 8051, the new CPU core runs at a much lower speed and thereby greatly reduces power consumption.