imx8mp gpio read two wait states

キャンセル
次の結果を表示 
表示  限定  | 次の代わりに検索 
もしかして: 

imx8mp gpio read two wait states

ソリューションへジャンプ
673件の閲覧回数
deangereaux
Contributor I

I have noticed when using the Linux /sys/class/gpio interface one of my input gpios toggles from 0 to 1 occasionally.  The input is held low constantly, but approximately every 5 minutes the input will toggle to 1 then immediately back.    I am doing a read (cat /sys/class/gpio77/value) every 500 msec.

Digging around the documentation, I noticed in the i.MX 8M Plus Applications Processor Reference Manual, Rev2, 02/2024, section 8.3.5.1.2.2 there's a statement:  "If a given GPIO direction bit is cleared, then a read of DR
register reflects the value of the corresponding signal. Two wait states are required in
read access for synchronization."

What wait states is this referring to?

Could this be the cause of the toggling I'm seeing?

 

Thanks,

Dean

0 件の賞賛
返信
1 解決策
625件の閲覧回数
deangereaux
Contributor I
My question about wait states has been answered by this previous post: https://community.nxp.com/t5/i-MX-Processors/GPIO-wait-states/m-p/356880

元の投稿で解決策を見る

1 返信
626件の閲覧回数
deangereaux
Contributor I
My question about wait states has been answered by this previous post: https://community.nxp.com/t5/i-MX-Processors/GPIO-wait-states/m-p/356880