Comparing the 8051
8 bit microcontollers are still in widespread use. At one time they were ideally suited to embedded systems, is this still true? A little analysis shows that they no longer have many advantages …
Speed
8 bit processors handle only 8 bit values, over an 8 bit bus. The limited instruction set takes many more instructions to do anything useful.The limited address space means that accessing memory or executing code frequently requires tedious bank switching, this overhead increases the time taken to do useful processing.
Area
The Cortus APS3 is only 10k gates, about the same size as some implementations of an 8051. Clearly the “King of Lilliput” (‘Itty-Bitty 32-Bitters’ – Microprocessor Report May 2009).Power Consumption
The APS3 does more with each clock pulse, and more work for each µW of power consumed compared with traditional 8 bit microcontrollers. in addition the small silicon footprint and rational design ensures that the power consumption remains tiny.See this paper presented at ERTS2010: The Advantages and Pitfalls of Moving to a 32 bit Architecture
