The online 8052 reference.
8051 Architecture from Atmel
Intel MCS 51 Microcontrollers - Classic
Atmel offers a broad range of microcontrollers based on the 8051 architecture.
Intel's 8-bit MCS® 51 family of microcontrollers is a leading choice for embedded control. This Classic family consists of CHMOS versions of all the original 8-bit microcontrollers that introduced the MCS 51 microcontroller family. Intel offers a wide variety of on-board memory in EPROM, ROM and OTP, as well as CPU-only microcontrollers. Intel's proven CHMOS technology provides lower power, higher integration and higher performance.