Hello,
I have a BeagleBone Black with a “Serial Cape” (http://www.logicsupply.com/eu-en/cbb-serial/). This cape supports RS-485 which i’m interested in. Before i had this cape, i used a RS-485-to-USB-converter.
My problem:
I try to read some data from an external device. It’s very simple: The request is just “/?!\r\n” and then i get the data.
With the RS485-to-USB-Stick i used this serial port configuration (with ser2net):
/dev/ttyUSB0 9600 7DATABITS EVEN 1STOPBIT
With the cape i tried this configuration:
/dev/ttyO4 9600 7DATABITS EVEN 1STOPBIT
Unfortunately this first try didn’t work. I didn’t get any response. I also tried this configuration:
/dev/ttyO4 9600 7DATABITS EVEN 1STOPBIT RTSCTS
I set the jumpers on the cape like this:
J8: RS485
J7: UART4 RTS
The RS485+ wire is connected to the RS485B port, and the RS485- wire is connected to the RS485A port.
(https://docs.google.com/document/d/1sgurQ-7gLyn7g-Kg983NRM0aDkYEqHqy9dmrieX_RUM/edit page7)
To get a better overview i made a photo:
At the bottom of the picture there is the RS485-to-USB converter. It just has two ports which i used to connect the RS485 wires.
I think the board itself should work, because if i execute “cat /sys/devices/bone_capemgr.*/slots” i can see it.
My question:
Do i do something wrong? Maybe someone else has used this cape with RS485? I thought it should be almost as easy as with the USB converter?
Thank you for any help
Best regards
Benj