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assert 和 deassert的意思

已有 3623 次阅读2010-4-22 16:21 | 关键词:

摘自 MAX6625 datashit:

Interrupt Mode
In interrupt mode, the MAX6625/MAX6626 look for a
THIGH or a TLOW fault based on previous fault activity.
The OT pin asserts an alarm for an undertemperature
fault, as well as for an overtemperature fault, depending
on certain conditions. If the fault queue is cleared at
power-up, the IC looks for a THIGH fault. After a THIGH
fault, the IC looks for a TLOW fault. After a TLOW fault,
the IC looks for a THIGH fault, and it bounces back and
forth if properly deasserted each time. Once either fault
has occurred, it remains active indefinitely until
deasserted by a read of any register, and the device
then begins to look for a fault of the opposite type. Also,
if the fault queue is cleared, OT is deasserted and the
IC once again looks for a THIGH fault. The activation of
any fault is subject to the depth of the fault queue.

--------------------------------------------------------
what is the meaning of 'assert'and 'deassert'?
assert: set a signal to its "active" state.-----做assert就是给设备一个使他活跃的信号。
deassert: set a signal to its "inactive state.-----做deassert就是给设备一个使他不活跃的信号。
If a signal is active-low, "asserting" that signal means
setting it low and deasserting it means setting it high.----如果一个signal是
active-low类型的,那么做assert就是给设备一个active-low的信号,就是让设备进入low的状态
做deassert就是让设备进入high的状态。
---------------------------------------------------------
总结:
assert -------让一个设备进入活跃的状态,deassert让设备进入对于assert做的相反的状态。


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回复 linux_Ultra 2010-4-22 16:34
mailing list上的:

Kingcosmos wrote:

    Homer J Simpson wrote:

        "ɽ֮á°" <lan54160@xxxxxxxxx> wrote in message

        In English, the term 'assert' can have more than one meaning.

        Deassert has a specific meaning and is the opposite of assert for only one
        of the uses of that word. In formal English there is no such word as
        deassert - it is an invented word for technical purposes.

        In this case I expect it means to set a logic output high (assert) or low
        (deassert). However you have to read it in context.


    Looks like this thread has ran its course but I would imagine that it
    is a combination of assert = ON and deassert = OFF regardless of a
    control pin being active high or active low. In either case you assert
    the pin to make it active and it wouldn't matter if it had to be high
    or low to do so. Same logic (no pun intended) for deasserting the pin.
    Like an output enable for example. That's the way I would look at it.


Definitely so.

Graham
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