Arduino mega 16Mhz RS485 115200 Baud rate

base on this Website, Arduino with 16Mhz clock will not reliable to run 11500 baud rate communication, and if this is true how can we lower the clock speed to do so.

I am trying to communicate RS485 with 115200 baud rate with HDLC protocol. This Website show all accepatable Frequencies.

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Are you using the hardware serial port or SoftwareSerial?

Also never had any problems with any of the baud rates. 250000 seems to be the only exact one, assuming the transmitter AND receiver are crystal clocked (most Arduinos are not). Leo..

I used both Hardware and Software serial and both had same problem. Error percentage was very high, and I was missing a lot of bytes.

Quick note: I am MAX485 TTL to RS-485 Module to communicate to 3rd party device.

Give us the full picture, including wire/length and termination resistors. Leo..

1.Wire length is only 8ft long. 2. I am using this Module 3. I am connecting the A and B to 3rd party device bus line 4. NO termination resistor, since I am the slave

Master is sending EXAMPLE 7E0510BF067E, But I get 7E7E or 7E057E, some time i get he whole thing.

Shahreza: Wire length is only 8ft long.

I am connecting the A and B to 3rd party device bus line

NO termination resistor, since I am the slave

What kind of wire.

Did you also connect grounds.

A termination resistor has to do with the characteristic impedance of the wire. The module you linked to has 120ohm fitted. I assume you're only using one slave.

http://yourduino.com/sunshop//index.php?l=product_detail&p=323 Leo..

  1. I don not know what gauge of cable I am using , but I am using the same cable to read data from computer, and also third party device(Master) use to communicate with other devices(Slave).

  2. I ground RE, DE, GND to my Arduino Ground.Since I am only receiving data.

  3. Yes I am using same module and as slave

  4. This is how connect Module (vist the Link)


|Master|-- |Max485| ---|Arduino Mega|


|

|

|Slave| (Master and Slave is 3rd party manufacture using PIC micro controller)

Wawa: What kind of wire.

Did you also connect grounds.

A termination resistor has to do with the characteristic impedance of the wire. The module you linked to has 120ohm fitted. I assume you're only using one slave.

http://yourduino.com/sunshop//index.php?l=product_detail&p=323 Leo..