i.mx8 UART0_RX and UART0_TX swapped

sergey_tarassen — Thu, 29 Apr 2021 14:53:55 GMT

Hello,

we want to use serial ports UART0 and UART2 of the i.MX8 on the following pins:

AB32 UART0_RX
AA29 UART0_TX
AD34 UART2_RX
AC35 UART2_TX

UART2 works correctly, however it looks like TX and RX pins of UART0 are swapped.

after executing "echo some text > /dev/ttyLP0" in linux data is coming on UART0_RX (AB32) pin. What could be causing RX/TX swap?

We use following UART configuration in device tree:

&lpuart0 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_lpuart0>; power-domain-names = "uart"; dma-names = "tx", "rx"; dmas = <&edma2 9 0 0>, <&edma2 8 0 0>; status = "okay"; }; &lpuart2 { pinctrl-names = "default"; pinctrl-0 = <&pinctrl_lpuart2>; status = "okay"; /delete-property/ power-domain-names; /delete-property/ dma-names; /delete-property/ dmas; }; pinctrl_lpuart0: lpuart0grp { fsl,pins = < IMX8QXP_UART0_RX_ADMA_UART0_RX 0x06000020 IMX8QXP_UART0_TX_ADMA_UART0_TX 0x06000020 >; }; pinctrl_lpuart2: lpuart2grp { fsl,pins = < IMX8QXP_UART2_TX_ADMA_UART2_TX 0x06000020 IMX8QXP_UART2_RX_ADMA_UART2_RX 0x06000020 >; };

Thank you in advance!

Re: i.mx8 UART0_RX and UART0_TX swapped

sergey_tarassen — Thu, 06 May 2021 08:25:04 GMT

Problem was caused due to missmatch between layout and schematics. Actually UART works as expected.

topic i.mx8 UART0_RX and UART0_TX swapped in i.MX Processors

i.mx8 UART0_RX and UART0_TX swapped

Re: i.mx8 UART0_RX and UART0_TX swapped