25 lines
1.5 KiB
Markdown
25 lines
1.5 KiB
Markdown
# Physical
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Physical is a library for interacting with the physical world from a computer. This can broadly be broken down into two
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categories:
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* Collecting and digitizing data from the physical world.
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* Controlling devices that take physical action.
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## Concepts
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The main concepts of Physical are:
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* Peripheral: A peripheral is a board that hosts physical I/O and usually does analog to digital conversion or
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digital to analog conversion. A peripheral cannot function on its own, it must be connected to a node. This is more
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narrow than the definition of a peripheral in embedded systems generally. Peripheral support is done on the basis
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of complete boards, not individual components like an ADC. Abstractions for individual components should be made
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separately, such as in BFPOWER drivers.
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* Node: A node hosts peripherals. A node can have a commander but does not need one. A node can ignore or even override
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commands from the commander. In a complex system, nodes are intended to be kept simple, less likely to
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encounter an error than the commander, and in some cases should check for obvious problems in commands from the
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commander.
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* Commander: A commander hosts nodes. It is possible for a device to be both a node and a commander at the same time,
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although it may not be the best idea to make such a setup. There is no concept of nesting commanders built into
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Physical. If some kind of abstraction for a computer that commands multiple commanders, which command nodes, is
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necessary, it should be made for that specific application. |