How to set IOMUX of iMX6 dual UART?

[yoshitanamura]

Hello dear,　

We have an urgent question about IOMUX. 
Is it possible to set IOMUX with using combination of DCE mode and DTE mode,
when we construct UART communication under condition of below?
If possible, could you tell us target register which should be set by software, and its sequence?

Condition
1.To use UART with connecting an external UART device
2.To use TX_DATA signal, RX_DATA signal, CTS_B signal, and RTS_Bsignal
3."hardflow control" is valid.
4.To use both TX_DATA signal and RX_DATA signal as DCE mode like attached figure.
5.To use both CTS_B signal and RTS_B signal as DTE mode like attached figure.

Current status
As condition #5, we'd like to only use cross-connection of CTS_B signal and RTS_B signal
into IOMUX.  
At first, we set UART1 as DCE mode on linux enviroment.
After that, we change IOMUXC_UART1_UART_RTS_B_SELECTION_INPUT register value from "01"
(DCE mode) to "00"(DTE mode).
But we can't transfer data to external device.  　

We'd like to transfer data to external device with using cross-connection above.
Could you tell us any resolution of that?
This is very urgent for us, so please give us any advices or comments as soon as possible. 

Thanks a lot.

Yoshi Tanamura　

[igorpadykov]

Hi Yoshi

UART IOMUX has fixed IO configuration as shown below, so combination

of DCE mode and DTE mode is not allowed.

UART1 is DCE mode has RTS as input, so changing IOMUXC_UART1_UART_RTS_B_SELECTION_INPUT

register value from "01" (select pad EIM_EB3 for UART3_RTS_B.) to "00"(select pad EIM_EB3 for UART3_CTS_B.)

will not work.

Best regards

igor

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[yoshitanamura]

Hi  Igor

Thank you for your answer about our question.

It was useful but  not good for us.

Because we need to transfer data with another method.

We will do our best to fix this problem. 

Thanks.

Yoshi