What is the difference between minimum mode and maximum mode?

Answer 1

Minimum mode in the 8086/8088 provides the functionality of the 8288 bus controller, which means that functions like HOLD, HLDA, WR-, M/IO-, DT/R-, DEN-, ALE, and INTA- come off of the 8086/8088.

Maximum mode means that these functions come off of the 8288, in somewhat enhanced form, and the pins are replaced with new meanings like RQ-/GT0-, RG-/GT1-, LOCK-, S2-, S1-, S0-, QS2, and S21, giving the processor extra capabilities.

Answer 2

Minimum mode in the 8086/8088 is where the MN/MX- pin is high.

In minimum mode, the processor provides the functionality of the 8288 bus controller, at the cost of losing some pins. The pins ALE, DT/R-, DEN-, INTA-, M/IO-, RD-, and WR- come off the processor in minimum mode, minimizing the amount of external logic required to build a small system.

In maximum mode, MN/MX- being low, you need to provide an 8288 bus controller to provide a decoded state of these pins. This frees up some of the processor's pins, making room for new functionality, such as RQ0-/GT0-, RQ1-/GT1-, LOCK-, QS0-, and QS1-. This functionality is appropriate for larger systems.