Coprocessor Configuration:How is the coprocessor and the processor connected?

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Coprocessor Configuration

A Coprocessor is a specially designed circuit on microprocessor chip which can perform the same task very quickly, which the microprocessor performs. It reduces the work load of the main processor. The coprocessor shares the same memory, IO system, bus, control logic and clock generator. The coprocessor handles specialized tasks like mathematical calculations, graphical display on screen, etc.

The 8086 and 8088 can perform most of the operations but their instruction set is not able to perform complex mathematical operations, so in these cases the microprocessor requires the math coprocessor like Intel 8087 math coprocessor, which can easily perform these operations very quickly.

Block Diagram of Coprocessor Configuration

How is the coprocessor and the processor connected?

• The coprocessor and the processor is connected via TEST, RQ-/GT- and QS₀ & QS₁ signals.
• The TEST signal is connected to BUSY pin of coprocessor and the remaining 3 pins are connected to the coprocessor’s 3 pins of the same name.
• TEST signal takes care of the coprocessor’s activity, i.e. the coprocessor is busy or idle.
• The RT-/GT-is used for bus arbitration.
• The coprocessor uses QS₀ & QS₁ to track the status of the queue of the host processor.