imx6sll sleep mode,uart wakeup ,loss data

[ilyyxfe]

to whom it may concern

hello!

i am using the imx6sllevk evaluation bsp for development

i set the ttymxc0 as wake up source

when the system into the ”mem ”　sleep mode,

i use 40bytes data to wakeup the system by ttymxc0.

the system wake up successfully, but it loss the begining of  data（almost  30bytes）

it only receiced the last 10 bytes data。

is it normal because of the cpu characteristic？

or i can make some change in souce so that i can  receive them all....

pls give me some advice

thank you

[igorpadykov]

Hi zhang

according to sect.45.8.2 UART Operation in System Stop Mode i.MX6SLL Reference Manual:

"When an asynchronous WAKE (awake) interrupt exits the ARM platform from STOP
mode, make sure that a dummy character is sent first because the first character may not
be received correctly."

https://www.nxp.com/docs/en/reference-manual/IMX6SLLRM.pdf 

Best regards
igor
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[ilyyxfe]

Dear Igorpadykov:

thank you for replying very much

about your advice，I have seen the sect. before.

but it just expressed "it will not the first character(the first bit or byte?)".

in my case, my ttymxc0 works in 115200 , it loss too many data（almost  30bytes）.

our system need to be awaked by the uart, and will check the data received.

is there anything I can do(modify the kernel soure or a better solution) to improve the situation？

looking forward your advice.

best regards

zhang

[igorpadykov · Accepted solution]

Hi zhang

I believe one can improve it using uart flow control.

Best regards
igor