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Reading a hardware bus specification, I frequently come across things like: "When the controller sees that a bus request has been made, it asserts the Bus Grant line to the first device."

What exactly does the term "assert" mean here? Is it as simple as "activate", or is there more to it?

toolic
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    In this case the "Bus Grant" might be an electrical low digital level so say ground, or maybe bus grant means it is a high signal. To avoid the problem of high vs low and the fact that for some signals active or asserted means high and sometimes active or asserted means low, we just say asserted vs not asserted, then you have to look at the electrical definition if that matters. For example reset is often asserted low so that you can use a simple RC circuit to bring it up a little slower than power so the part has time to power up before reset is released. – old_timer Aug 06 '18 at 06:04
  • I think you get it there isnt anything magical about it, based on your text bus grant asserted means the bus is granted, bus grant de-asserted or not asserted means the bus is not granted. – old_timer Aug 06 '18 at 06:05
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    I'm voting to close this question as off-topic because it is not a computer programming question. It appears to be a processor design / electrical engineering question. – Raymond Chen Aug 06 '18 at 06:06

1 Answers1

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Old Timer has basically answered this but to summarise:

"Assert" means "set to active state" (or "activate" as you said), which could be HIGH or LOW. This is in contrast with "set", which always means "set to HIGH", and "clear", which always means "set to LOW", regardless of which of HIGH or LOW is the active state.

Ed Graham
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