IMX6 : swap debug uart pin

[Cécile]

Hello,

I'm trying to invert the Tx and Rx pin of the UART1 debug bus, on the sabresd board.
I try to change to DTE mode like this :

mx6sabresd.c

static iomux_v3_cfg_t const uart1_pads[] = {
IOMUX_PADS(PAD_CSI0_DAT11__UART1_TX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL)),
IOMUX_PADS(PAD_CSI0_DAT10__UART1_RX_DATA | MUX_PAD_CTRL(UART_PAD_CTRL)),
};

imxqdl-sabresd.dtsi

pinctrl_uart1: uart1grp {
fsl,pins = <
MX6QDL_PAD_CSI0_DAT11__UART1_TX_DATA 0x1b0b1
MX6QDL_PAD_CSI0_DAT10__UART1_RX_DATA 0x1b0b1
>;
};

[...]

&uart1 {
pinctrl-names = "default";
fsl,dte-mode; 
pinctrl-0 = <&pinctrl_uart1>;
status = "okay";
};

But it doesn't work...
What am I missing?

Thank you for your help !

Cécile

[Dhruvit]

hello @Cécile ,

I hope You are doing well.

->The chip-level IOMUX modifies the direction and routing of the UART signals based on whether the UART is operating in DCE mode (UARTn_UFCR[DCEDTE]=0) or DTE mode (UARTn_UFCR[DCEDTE]=1). So one should always set DTE Mode.(UARTn_UFCR[DCEDTE] = 1)

->For DTE Mode One has to configure the pin setting of UART1_RX/TX_DATA & UART1_CTS/RTS_B as shown in the attachments. I've attached the attachments for the reference , please find the same.

Thanks & Regards

Dhruvit Vasavada

[Dhruvit · Accepted solution]

Hi @Cécile 

Please find the attachments.

Thanks & Regards

Dhruvit Vasavada