Editing Intel 8086 (section)

===Hardware modes of 8086===
Some of the control pins, which carry essential signals for all external operations, have more than one function depending upon whether the device is operated in ''min'' or ''max'' mode. The former mode is intended for small single-processor systems, while the latter is for medium or large systems using more than one processor (a kind of multiprocessor mode). Maximum mode is required when using an 8087 or 8089 coprocessor. The voltage on pin 33 (MN/{{overline|MX}}) determines the mode. Changing the state of pin 33 changes the function of certain other pins, most of which have to do with how the CPU handles the (local) bus.<ref group="note" >The IBM PC and PC/XT use an Intel 8088 running in maximum mode, which allows the CPU to work with an optional 8087 coprocessor installed in the math coprocessor socket on the PC or PC/XT mainboard. (The PC and PC/XT may require maximum mode for other reasons, such as perhaps to support the DMA controller.)</ref> The mode is usually hardwired into the circuit and therefore cannot be changed by software. The workings of these modes are described in terms of timing diagrams in Intel datasheets and manuals. In minimum mode, all control signals are generated by the 8086 itself.