• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 100 subscribers
  • Views 219 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

Original question:

AM3354: UART RTS as RS485 Direction Control and RS232 RTS

AM3356: UART RTS as RS485 Direction Control and RS232 RTS

Smrithy TR
Prodigy 190 points
Part Number: AM3356

Hello Sir,

We have tried the solution suggested in the post. But RS485 Mode is not working as intended with that settings.

On further analysis, we came to know that there is an another serial driver (8250). We are using the Linux kernel version 4.14.67, and the serial driver we are using is omapserial. Is it necessary to use the 8250 serial driver in order to enable RS485 Mode as suggested in thread(with 'TIOCSRS485 ioctl' and 'RTS pin for direction control')? If so, does the kernel version 4.14.67 include a complete implementation of RS485 using the RTS line associated with that port?

  • 0
    TI__Guru**** 156131 points

    Hi Smrithy,

    I would have to check the TI SDK with kernel v4.14.67 to see if the default UART driver is omap_serial or 8250_omap. I will get back to you.

  • 0 in reply to Bin Liu
    Prodigy 190 points

    Hi Bin Liu,

    Thank you so much for the quick reply.

    I need clarification on the following  point too.

    Does the 8250 driver in version 4.14.67 support RS485 and RS232, using RTS as the pin for direction control and flow control, respectively? If the driver fully supports these functionalities and allows mode switching through the described IOCTLs as you described with the 8250 driver, our plan is to transition to the 8250 driver and eliminate the GPIO-based configuration (DTS) currently used for RS485 operation. Presently, we maintain two different DTBs, which necessitates a reboot to switch between RS485 and RS232 modes for the port.

    If this is feasible, please also guide us on how to switch to the 8250 driver.