How to connect RS485 device with PSoC4.

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Anonymous
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Hi,

   

I am using BLE Pioneer Kit (CY8CKIT-042-BLE) and trying to connect RS485 device to PSoc4.

   

The datasheet of UART component of PSoC4 tells "The UART provides asynchronous communications commonly referred to as RS232 or RS485".

   

As I know, 2 pins (TRXD+, TRXD- or A, B) are used for RS485 communication and these 2 pins are not dedicated "input pin" or "output pin".
So I think "input pin" and "output pin" of this UART component should be changed to (TRXD+, TRXD- or A, B) if it will be used for RS485 mode, but it seems not to be changed.
Can you please let me know how to connect RS485 device (it have 2 pins - TRXD+ and TRXD-) with UART component (it seems to have only dedicated input and output pin) of PSoC4?

   

Thanks
William

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Bob_Marlowe
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With TRXD+ and TRXD- you are referring to the differential line driver which you need the PSoC4 connect to. Like the "normal" RS232  UART needs a driver to get +-12V signal the RS485 needs this differential driver for the transmission on longer lines. The connections to the driver are the Tx,Rx and enable lines which are provided by the PSoC4.

   

 

   

Bob

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Anonymous
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Hi Bob,

   

 

   

Thanks for your help.

   

It will be helpful to me.

   

 

   

Thanks,

   

William.

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Bob_Marlowe
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You are always welcome, William!

   

 

   

Bob

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Anonymous
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        I am using psoc4 cy8c4245axi micro controller and trying to develop modbus slave device and got sucess to build up modbus slave in RS-232 but when we interface RS-485 it get problem so pl help me about RS485   
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Bob_Marlowe
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Your problems seem to be related to the driver level. Are you using a driver IC and did you enable the hardware tx-enable?

   

 

   

Bob

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EvPa_264126
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For the RS-485 contact is required to control the direction of transmission, so SCB  i can not use.
I use a cheap driver (see picture)

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Anonymous
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Thanks ,

   

I tried to Connect as per image , i also use max485 ic....but i am facing some frequency related warning when i build the project ..

   

if it is possible can you share some code on  Max-485 interfacing

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EvPa_264126
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A special code is not necessary - it is a regular UART.
You just need to turn on "Hardware TXEnable".

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Hi,

I want to reuse a code made in psoc3 for a 485 communication, but the uart is totally different in psoc 4. How I reuse the pins?

How can I do to generate the interrupt byte received and transmitted byte?

ThanksUART_PSOC3vsPsoc4.jpg

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