|Discontinued||September 28, 2007|
|Max. CPU clock rate||6 MHz to 25 MHz|
|FSB speeds||6 MHz to 25 MHz|
|Data width||16 bits|
|Address width||20 bits|
|Architecture and classification|
|Technology node||3 µm|
|Co-processor||8087 and later, 80187 (for 80186 only)|
|Products, models, variants|
|Successor(s)||Intel 80386 (The 80286 was also introduced in early 1982, and thus contemporary with the 80186)|
The Intel 80186, also known as the iAPX 186, or just 186, is a microprocessor and microcontroller introduced in 1982. It was based on the Intel 8086 and, like it, had a 16-bit external data bus multiplexed with a 20-bit address bus. The 80188 variant, with an 8-bit external data bus was also available.
The 80186 series was generally intended for embedded systems, as microcontrollers with external memory. Therefore, to reduce the number of integrated circuits required, it included features such as clock generator, interrupt controller, timers, wait state generator, DMA channels, and external chip select lines.
The initial clock rate of the 80186 was 6 MHz, but due to more hardware available for the microcode to use, especially for address calculation, many individual instructions completed in fewer clock cycles than on an 8086 at the same clock frequency. For instance, the common register+immediate addressing mode was significantly faster than on the 8086,[a] especially when a memory location was both (one of) the operand(s) and the destination. Multiply and divide also showed great improvement, being several times as fast as on the original 8086 and multi-bit shifts were done almost four times as quickly as in the 8086.
A few new instructions were introduced with the 80186 (referred to as the 8086-2 instruction set in some datasheets): enter/leave (replacing several instructions when handling stack frames), pusha/popa (push/pop all general registers), bound (check array index against bounds), and ins/outs (input/output of string). A useful immediate mode was added for the push, imul, and multi-bit shift instructions. These instructions were also included in the contemporary 80286 and in successor chips.[b]
The (redesigned) CMOS version, 80C186, introduced DRAM refresh, a power-save mode, and a direct interface to the 80C187 floating point numeric coprocessor. Intel second sourced this microprocessor to Fujitsu Limited around 1985. Both packages for Intel 80186 version were available in 68-pin PLCC and PGA in sampling at third quarter of 1985. The available 12.5 MHz Intel 80186-12 version using the 1.5-micron HMOS-III process for USD $36 in quantities of 100. The available 12.5 MHz Intel 80C186 version using the CHMOS III-E technology using approximately 90 mA under normal load and only 32 mA under power-save mode. It was available in 68-pin PLCC, CPGA, or CLCC package. The military version of Intel M80C186 embedded controller was available in 10 and 12 MHz version. They met MIL-STD-883 Rev. C and MIL-STD-1553 bus application standards. The 12 MHz CHMOS version consumes approximately 100 mA. The available packages were 68-pin CPGA and CQFP. The 10 MHz M80C186 PGA version was available for USD $378 in 100-unit quantities.
Because the integrated hardware of the 80186, designed with embedded systems in mind, was incompatible with the hardware used in the original IBM PC, the 80286 was chosen to succeed the 8086, in the IBM PC/AT and other PC-compatible systems.
Several notable personal computers used the 80186:
In addition to the above examples of stand-alone implementations of the 80186 for personal computers, there were at least two examples of "add-in" accelerator card implementations: the BBC Master 512, Acorn's plug-in for the BBC Master range of computers containing an 80186-10 with 512 KB of RAM, and the Orchid Technology PC Turbo 186, released in 1985. It was intended for use with the original Intel 8088-based IBM PC (Model 5150).
The Intel 80186 is intended to be embedded in electronic devices that are not primarily computers. For example:
In May 2006, Intel announced that production of the 186 would cease at the end of September 2007. Pin- and instruction-compatible replacements might still be manufactured by various third party sources, and FPGA versions are publicly available.