THVD1520: do I need preamble or sync bytes for THVD1520 RS485 bus protocol?

cheng gu

Prodigy 90 points

Part Number: THVD1520

Tool/software:

Hi Team,

we are using THVD1520 to connect our devices using RS485. the requirement is 3000 feet @ 115200 bps.

do I need send some preamble bytes or sync bytes before I send out the real packet on the RS485 bus?

I looked through the forum of RS485 bus related posts but can't find any discussion of it. would you please advise? thanks.

Best
Gu

over 1 year ago

0 Ethan Sempsrott over 1 year ago

TI__Mastermind 18172 points

Hi Gu,

RS-485 can support up to 4000ft at <=100Kbps if setup correctly setup according to the RS-485 PHY standard. The reason you probably could not find any results is because RS-485 only defines the physical layer and not the data layer since that is up to the designer. I would recommend following our design guide for the best signal integrity: https://www.ti.com/lit/an/slla272d/slla272d.pdf

Preamble bytes are not required but could be added if you deem it beneficial.

Best,

Ethan

Interface

Interface forum

THVD1520: do I need preamble or sync bytes for THVD1520 RS485 bus protocol?