Messages in this thread | | | From | Fabio Estevam <> | Date | Fri, 6 Jan 2017 19:22:32 -0200 | Subject | Re: imx: RS-485 problems during TX, maybe DMA related |
| |
Hi Clemens,
On Wed, Jan 4, 2017 at 2:00 PM, Clemens Gruber <clemens.gruber@pqgruber.com> wrote: > Hi, > > I observed odd behavior of the current tty/serial/imx.c driver in RS-485 > mode. > > RX works fine, but TX does not: When sending data, it arrives multiple
I am also trying to get rs485 in half-duplex mode to work on mx6dl with kernel 4.9.
RX also works for me, but TX does not.
On my board it is the MX6QDL_PAD_CSI0_DAT16__UART4_RTS_B pin that controls the rs485 transceiver flow, but I do not see RTS to toggle to 1 during transmit. It stays always at 0.
I see you use CTS pin instead, but I thought RTS pin should be used.
On my userspace application I have:
/* enable RS485 mode: */ rs485conf.flags |= SER_RS485_ENABLED;
/* set logical level for RTS pin equal to 1 when sending: */ rs485conf.flags |= SER_RS485_RTS_ON_SEND;
/* set logical level for RTS pin equal to 0 after sending: */ rs485conf.flags &= ~(SER_RS485_RTS_AFTER_SEND);
Any ideas as to how to make RTS go to one so that the data can go through the rs485 transceiver?
Thanks
| |