Idle state of RTS in RS-485 mode on IMX6

[jeff_hunsinger]

I activated RS-485 mode on the IMX6UL using UART7 and the RTS pin transitions as expected when I have the port open. However, when I close the port, the pin goes high even though I have it configured to be low when not transmitting. There is an external pull-up on this pin because it is used to configure the IMX6UL at reset.

Is there a way to have the pin drive low by default when the UART is not open?

I am using the LCD_DATA06_DTE_RTS pin with the UART in DCE mode.

I use the following to enable RS-485 mode in the Linux driver:

rs485conf.flags |= SER_RS485_ENABLED;
rs485conf.flags |= (SER_RS485_RTS_ON_SEND);
rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);

ioctl(fd, TIOCSRS485, &rs485conf);

Thank you,

Jeff

[igorpadykov]

Hi Jeff

one can try to change behavior adding codes in driver configuring

that pad as gpio, with low state by default when the UART is not open.

Best regards
igor
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