SN65HVD33: How to set up transceiver to be able to communicate with slave

Hello,

The SN65HVD33 device is simple from a hardware perspective.  To send data, pull "DE" (driver enable) high and send the serial data on "D" - the differential output(pins Y, Z) will then switch between high and low states according to the status of the "D" signal.  To receive data, pull "/RE" (receive enable) low and the "R" output will toggle high and low based on the differential voltages on the bus (pins A, B).  Typically the Y/Z output from the master will connect to the A/B inputs of the slave nodes for "downstream" communication and the Y/Z outputs from the slaves will connect to the A/B inputs of the master for "upstream" communication.

The transceiver device doesn't require any particular data formatting - it implements only a physical layer function according to the RS-485 standard (which defines physical characteristics like voltage levels and not data link layer parameters like frame formatting or bus access requirements).  So, the data protocol used is flexible.  Modbus RTU should work if you have a driver for it.  (The driver wouldn't be specific to the transceiver - it would most likely just use the MCU's UART ports.  I would expect it to be more specific to the MCU.)

Please let me know what further questions you have.

Regads,
Max

Hi Max,

Thanks for quick response.

Could you share any modbus RTU driver ?

Cheers

Hello,

Unfortunately I don't know of any driver provided by TI for this.  If you are using a TI MCU I could check with that team directly to see if they know of anything.  Otherwise, it looks like this site may be useful to you:

https://www.embedded-experts.at/en/freemodbus/about/

Regards,
Max

Hi,

Thanks  Max,Can you share an example of SN65HVD33 with TI MSP430F as a master  ?

I will notify the MSP430 team about this thread to see if they have any references that may be useful to you.

Max