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);