C8051: Legacy-Speed 8-Bit Processor Core

"Features
8-bit Control Unit
8-bit Arithmetic-Logic Unit with 8-bit multiplication and division
Instruction decoder
Four 8-bit Input /Output ports
Two 16-bit Timer/Counters
Serial Peripheral Interface in full duplex mode
Synchronous mode, fixed baud rate
8-bit &9-bit UART mode,variable baud rate
9-bit UART mode, fixed baud rate
Multiprocessor communication
Two Level Priority Interrupt System
5 Interrupt Sources
Internal Clock prescaler and Phase Generator
256 bytes of Read/Write Data Memory Space
64KB External Program Memory Space
64KB External Data Memory Space
Services up to 107 External Special Function Registers
Power Management Unit ports stop and idle modes Optional Features
Fast Multiplication-Division Unit
16 x 16 bit multiplication
32 /16 bit division
16 /16 bit division
32 bit normalization
32 bit L/R shifting
Compare/Capture Unit
Four 16-bit Compare registers used for Pulse With Modulation
Four external Capture inputs used for Pulse With Measuring
16-bit Reload register used for Pulse Generation
Programmable Watchdog Timer
Third 16-bit Timer/Counter
Second Serial Peripheral Interfaces
Real Time Clock"