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Control of peripheral
devices
(2)
makers do not attempt to produce a different interface chip for every
type of application, but market only one or two 'general-purpose' types,
which are highly adaptable. This flexibility makes the circuits seems
complicated, and the documentation, if read 'in the abstract', is often
difficult to understand. However, if the reader has a specific problem in
mind, these difficulties form much less of a barrier than might be
expected.
The
6820
general-purpose
interface controller
Motorola's 6820 can be used to control all parallel interfaces. It takes
over data latching, data buffering, status recording, interrup ...