Modbus(RS485) communication using UART1 on Nrf9160

RE: Modbus(RS485) communication using UART1 on Nrf9160

Maria Gilje — Thu, 01 Sep 2022 07:16:05 GMT

Hello,

[quote user="Waqar Ahmed"]Problem is resolved, I had successfully established the Modbus communication on nrf9160.
[/quote]

Great to hear!

Thank you for sharing your solution.

BR,

Maria

RE: Modbus(RS485) communication using UART1 on Nrf9160

Waqar Ahmed — Wed, 31 Aug 2022 13:00:44 GMT

Hi Maria,

Thanks for your reply.

Problem is resolved, I had successfully established the Modbus communication on nrf9160.

The Reason for the error:

https://devzone.nordicsemi.com/f/nordic-q-a/48478/custom-board-based-on-nrf9160-gpio-pin-mapping-problem

Some UART registers don't change after changing in .overlay

and Secondly:

in our custom board we are using separate enable /disable signal for RX/TX communication.
so its difference of time due to which communication is not enabled on time.
so after analyzing the signal on communication on logic analyzer and then sync the communication.

Thanks

RE: Modbus(RS485) communication using UART1 on Nrf9160

Maria Gilje — Wed, 31 Aug 2022 12:02:52 GMT

Hello Waqar,

Sorry for the late reply.

I have been reading up on the modbus samples to try to help you along. The function casting the error is modbus_write_holding_regs which has a two options for the reason for the error: no device (ENODEV) and no buffer space (ENOBUFS). Finding which one is causing the error will help you move forward.

Setting up the UART1 in the devicetree or overlay for your board and making sure that the status is "okay" is the way to enable using UART1.

[quote user="Waqar Ahmed"]

on my custom board the tx and Rx pins numbers are different.

i have makes changes accordingly.

[/quote]

Have you made the changes in a .dts or .overlay file? Sharing your code may also be helpful. This ticket can be made private if your code contains sensitive information.

BR,

Maria

RE: Modbus(RS485) communication using UART1 on Nrf9160

Waqar Ahmed — Wed, 24 Aug 2022 19:11:11 GMT

Yes,

for the above problem i found a way there is bug in zephyr api.

At no parity mode. Zephyr use 2 stop bits.that y i am getting this error.

with nrf9160 dk i am able to communicate with modbus server.

now i am facing an other issue which is related to UART1 on my custom board.

i am getting the same error.

on my custom board the tx and Rx pins numbers are different.

i have makes changes accordingly.

but i am unable to communicate with modbus.

please guide regarding to UART1 setup.

RE: Modbus(RS485) communication using UART1 on Nrf9160

Maria Gilje — Fri, 19 Aug 2022 11:59:36 GMT

Hello Waqar,

The Zephyr Project team or community should be able to help you. Contact information is found on their website. I recommend that you post your issue in their Discord server.

Best regards,

Maria