implementation rs-485 Tiva C series

Hi Andre,

Unfortunately, I do not know the answer to this off-hand, so I am going to move this question to the TIVA C forum so they can help you.

We deal with the physical layer and transceiver portion of RS485 in the industrial interface forum.

Thanks!

John

You don't need a library, but some external HW like the MAX489. Connect it to a UART of the Tiva micro and setup some GPIO pin as the enable to control the bus.

One point not really detailed yet, this thread - arises should yours be beyond a 2 device, RS-485 bus.  As friend PAk SY noted - RS-485 transceiver should have its driver (output side) disabled unless & until it seeks to transmit.  As stated, a gpio pin may handle - but this demands added software to detect the start, then the end, of the RS-485 transmission.  (so that the transceiver minimizes its time w/in the TX mode.  i.e. to prevent bus contention/collision)

A simplifying solution would employ the more "complete" UART Port w/in your MCU.  Such port would include the normal/customary modem signals - from days past.  These should be auto-generated - and may properly switch your 485 xcvr. into TX - only when and as needed. 

One especially neat device (imho) LTC2870 which includes both RS-485 & RS232 (one at a time, usage).  This device includes a "DEN" pin which potentially extends "multi-drop" bus to RS-232.  (this due to the ability to have each/every level/shifter/transceiver returning to "read" always - switching only to tX when DXEN is pounded)

Hello,

Andre, in case you are also looking for a transceiver, I thought I could give you some of the transceiver solutions from TI! We offer a large portfolio of transceivers both half and full duplex, with and without enables. Please let me know if you have any questions.

I think Andre is after software that will automatically do this for him. Like API calls he could use for sending, and interrupts for when messages are received.

Thanks,

John

cb1_mobile said:

A simplifying solution would employ the more "complete" UART Port w/in your MCU.  Such port would include the normal/customary modem signals - from days past.  These should be auto-generated - and may properly switch your 485 xcvr. into TX - only when and as needed. 

Good idea.

Which would be  the modem pin that could work as enable?

Thank you

PAk benef said:

Which would be  the modem pin that could work as enable?

Mon ami - might we leave some, small detail to the reader?  (heavy lifting {this idea} this guy's contribution...)

hint: (such signal should toggle high - just prior to TX commencememt - and return low - just after last TX bit has completed.)  Beauty - this method - "escapes" any added SW "burden."

Here's something more helpful. Use the RTS pin.