May 2014
Intermediate to advanced
320 pages
13h 41m
English
Content preview from Servicing Personal Computers, 3rd Edition
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230 Servicing Personal Computers
In the case of the PC family and compatibles, interrupts are managed by one or more 8259A
programmable interrupt controller (PIC) devices. These versatile chips are described in detail
later in this chapter.
Modes of operation
The 8086 and 8088 can operate in one of two modes: 'max' and 'min' determined by the
logical state of pin-33 (MN/MX). Minimum mode is selected when this pin is taken
high.
Conversely, maximum mode is selected when this pin is taken low. Maximum mode must be
selected for coprocessor/multiprocessor applications (e.g. to allow an 8087 mathematics
coprocessor to share the instruction stream ...