I am trying to interface Waveshare RSBL85-12 servo with jetson nano directly through SP3485 (MAX485).
I have attached hardware connections and simple code with which I am trying to ping the servo.
I am unable to ping servo as well as the loopback test at MAX485 A-B output is failing.
(I have already tried multiple baudrates and IDs)
Hi sankalp_TL,
Are you using the devkit or custom board for Jetson Nano?
What’s the Jetpack version in use?
Which UART interface you are connecting from Jetson Nano?
Have you verified UART loopback test working by simply short TX/RX before connect with SP3485?
RTS has the opposite behavior of DE/RE, so you may need to invert it for RS485 converter(SP3485).
Hi KevinFFF, thanks for getting back!
I am using jetson nano super dev kit ;
Jetpack version - latest from here (setup 2 weeks ago);
UART1/a from 40 pin header (/dev/ttyTHS1) - Pin 8 (TX), Pin 10 (RX), Pin 11 (RTS);
Yes, I verified the loopback test- It is working.
inverting RE/DE in terms of logic or hardware connections? hardware connections of RE/DE are connected together internally on SP3485. I also have other max485 board which has RE/DE separate
Hope I answered your questions.
It seems you are using Orin Nano rather than Jetson Nano.
I’ve moved your topic to correct category for Orin Nano.
You can refer to the following thread for the similar use case to invert RTS.
Need to Invert UART2 RTS - #11 by KevinFFF
For the UART1 from 40 pins expansion header, the register should be 0x03100020.
$ sudo busybox devmem 0x03100020 w 0x8
$ sudo busybox devmem 0x03100020
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