This article is from the Robotics FAQ, by Kevin Dowling firstname.lastname@example.org with numerous contributions by others.
An 80C186 is a evolution from the 8086. It is an embedded processor
sold by Intel, and has the same instruction set as the 8086, with the
additional "real-mode" instructions of the 286. It has the same 16-bit
data and 20-bit address bus structure of the 8086. The 80C188 is an
8-bit data bus version, just like the 8088 (of PC and PC/XT fame). For
embedded systems, it is much easier to use than the 8086.
It has an on-chip timer system, interrupt controller, DMA controller,
and clock generator. For DRAM operation, it also has an integrated
DRAM refresh generator. However, it has no on-chip I/O, nor does it
have any memory on-chip. There is, however, extra circuitry for
selecting external memory with a minimum of extra logic. Can be
programmed using most DOS compilers and assemblers, but requires a
linker that knows about locating code in absolute memory.
The '186 is not as accessible; it is harder to set up, the tools cost
more, and robotics and control resources have to be added externally.
The timers can be configured for PWM or pulse timing, It does,
however, run at higher speeds, have more accessible memory, and can be
hooked up to a floating-point co-processor (C187). It looks a lot like
a DOS machine. This may be important when software is run on multiple
platforms and also helps with the learning curve.
[18.4] Intel 8051 (Robotics Microcontroller)
A typical 8051 contains:
CPU with boolean processor
5 or 6 interrupts: 2 external, 2 priority levels
2 or 3 16-bit timer/counters
programmable full-duplex serial port (baud rate provided by one
of the timers)
32 I/O lines (four 8-bit ports)
RAM and ROM/EPROM in some models
The 8051 and varients are now sourced by more than a half-dozen
companies including Intel, AMD, Dallas, Signetics, Siemans and others.
The 8051 FAQ can be found at:
It includes 8051 ftp sites, public domain langauges, commercially
available software and publications for the 8051.
[18.5] Intel 8096 (Robotics Microcontroller)
It is 16 bit, many registers, internal RAM, the usual compliment of
on-board peripherals (serial, A/D, pwm, timer/counters, etc)