8088 address/data bus lines are multiplexed – and contain the rightmost 8 bits of the memory address or I/O port number whenever ALE is active (logic 1) – or data whenever ALE is inactive (logic 0).
#8088 5MHZ MEMORY SPEED NS PRO#
No more than 10 loads of any type should be connected to an output pin without buffering – if this factor is exceeded, noise will begin to take its toll in timing problems The Intel Microprocessors: 8086/8088, 80186/80188, 80286, 80386, 80486 Pentium, Pentium Pro Processor, Pentium II, Pentium, 4, and Core2 with 64-bit Extensions.
Reduction in noise immunity may result in problems with long wire connections or too many loads.
– noise immunity is the difference between logic 0 output voltage and logic 0 input voltage levels
This difference reduces the noise immunity from 400 mV (0.8 V – 0.45 V) to 350 mV.
– a difference of 0.05 V The Intel Microprocessors: 8086/8088, 80186/80188, 80286, 80386, 80486 Pentium, Pentium Pro Processor, Pentium II, Pentium, 4, and Core2 with 64-bit Extensions
Standard logic circuits have a maximum logic 0 voltage of 0.4 V 8086/8088 has a maximum of 0.45 V.
The logic 1 voltage level of the 8086/8088 is compatible with most standard logic families.
Table 9–2 illustrates output characteristics of all the output pins of these microprocessors.
The input current levels are very small because the inputs are the gate connections of MOSFETs and represent only leakage currents.
Table 9–1 depicts input voltage levels and the input current requirements for any input pin on either microprocessor.
Input characteristics of these microprocessors are compatible with all the standard logic components available today.
This knowledge allows hardware designers to select proper interface components for use with the microprocessor – without the fear of damaging anything.
– and the output current drive capability for an output pin
It is impossible to connect anything to a microprocessor without knowing input current requirement for an input pin.
– and function in temperature extremes of –40° F through +225° F The Intel Microprocessors: 8086/8088, 80186/80188, 80286, 80386, 80486 Pentium, Pentium Pro Processor, Pentium II, Pentium, 4, and Core2 with 64-bit Extensions
80C88 and 80C86 are CMOS versions that require only 10 mA of power supply current.
Both microprocessors operate in ambient temperatures of between 32° F and 180° F.
– 8086 uses a maximum supply current of 360 mA – 8088 draws a maximum of 340 mA
Both microprocessors require +5.0 V with a supply voltage tolerance of ☑0 percent.
thus 8086 transfers 16-bit data more efficiently The Intel Microprocessors: 8086/8088, 80186/80188, 80286, 80386, 80486 Pentium, Pentium Pro Processor, Pentium II, Pentium, 4, and Core2 with 64-bit Extensionsįigure 9–1 (a) The pin-out of the 8086 in maximum mode (b) the pin-out of the 8086 in minimum mode.
Data bus width is the only major difference.
– 8086 has pin connections AD0–AD15 – 8088 has pin connections AD0–AD7
8086 is a 16-bit microprocessor with a 16-bit data bus 8088 has an 8-bit data bus.
– both are packaged in 40-pin dual in-line packages (DIPs)
Figure 9–1 illustrates pin-outs of 8086 & 8088.
In addition, we discuss the DC characteristics to provide a basis for understanding the later sections on buffering and latching.
In this section, we explain the function and the multiple functions of each of the microprocessor’s pins.
These simple microprocessors are explained as an introduction to the Intel microprocessor family.
In this chapter, the pin functions of both the 80 microprocessors are detailed and information is provided on the following hardware topics: clock generation, bus buffering, bus latching, timing, wait states, and minimum mode operation versus maximum mode operation.
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