i.MX93 RS485 half duplex without Rx enable gpio

[phil331]

Hi,

I'm using the i.MX93 with RS485 on Linux, but the hardware doesn't have a separate gpio for controlling the transceiver's receive enable pin, so the hardware echos anything that is transmitted.

On a Raspberry Pi, the pl011 driver handles this by disabling the uart's receive enable when transmitting and the SER_RS485_RX_DURING_TX flag is not set.

I tried to implement the same for the lpuart, but it looks like lpuart32_tx_empty() returns non-zero whilst there is still data in the fifo.

Any ideas?

Thanks, Phil

[joanxie]

I've mailed to you pls check