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4 MICROCOMPUTER INSTRUMENTATION AND CONTROL

Figure 4.16
Integrated Circuit
Chip Microprocessor

FPO

I/O Parallel Interface
Microcomputers require interface devices that enable them to
communicate with other systems. The digital buffer interface used in the
driver’s seat application discussed earlier is one such device. The digital buffer
interface is an example of a parallel interface because the eight buffer lines are
all sampled at one time, that is, in parallel. The parallel buffer interface in the
driver’s seat application is an input, or readable, interface. Output, or writable,
interfaces allow the microcomputer to affect external logic systems. An output
buffer must be implemented using a data latch so that the binary output is

126 UNDERSTANDING AUTOMOTIVE ELECTRONICS