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Sticky bits

Summary: 4 Replies, Latest post by danaaknight on 04 Dec 2014 04:20 PM PST
Verified Answers: 0
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user_228878049's picture
152 posts

 Hello ALL

I was going through the SPI datasheet and near TX and RX status register part i found this word "Sticky bits"

What are sticky bits

user_1377889's picture
9284 posts

Sticky bits keep their value when they changed to logical 1 as long until the status-register is read by the CPU. This is very important when the sticky bit is generating an interrupt, it has to be cleared within the isr. Otherwise the interrupt handling will not function properly.



Alex Lin's picture
1 post

 Thanks, Bob. Clear and concise.

user_1377889's picture
9284 posts

Alex, welcome in the forum and in the fascinating world of PSoCs!

Nice to see that you found this two-year old post of mine ;-)

Can I help you with something more actual?



user_14586677's picture
7646 posts

From the TRM


Sticky Status, with Clear on Read

In this mode, the status register inputs are sampled on each
cycle of the status and control clock. If the signal is high in a
given sample, it is captured in the status bit and remains
high, regardless of the subsequent state of the input. When
the CPU or DMA reads the status register the bit is cleared.
The status register clearing is independent of mode and
occurs even if the UDB clock is disabled; it is based on the
bus clock and occurs as part of the read operation.


Regards, Dana.

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