SBL2E-200 in RS-485 Half-Duplex

[LYN]

HI,
I worked with the SBL2E-200 in 2011, at that time everything was fine in RS-485 Half-duplex. Today I Copy & Paste that old design and I can’t make the PORT0 /RTS pin to move.

- It is the same on 3 different module: Firmware Version: SBL2E v1.65 Oct 4 2012
- PORT 1 work fine in debug and respond to AT command in RS-232 mode.
- PORT 0 work fine and respond to AT command RS-485 / Half-Duplex mode. I see it on the scope and manage to put a second 3.3 volts RX serial port to spy the SBL2E transmission.
-I know about inverting the PORT0/ RTS signal to control the half-duplex communication.
- I made the PORT0/RTS pin toggle by setting it in RS-232 and Hardware flow control so the signal is free to move and it is just driving the 3.3 volts MAX driver.

To me I’m missing a configuration or something as change in the firmware.

Thank you for your input and sorry to bother you with something that I know it’s working fine!
Lyn

[TomNB]

Are you compiling with the same tool set? What version are the tools?

What are you copying your old 485 code into?

When you load the old .s19 image without any changes, does it still work?

[LYN]

HI Tom,
I’m using the SBL2E-200

“NetBurner SBL2e Devices network-enable serial, analog, or digital I/O devices out of the box - no programming or development is required”

On the WEB configuration page it is noted: Firmware Version: SBL2E v1.65 Oct 4 2012
I don’t mind changing the Firmware but I don’t think I should have to compile one.

Thank you
Lyn

[TomNB]

Hello Lyn,

Sorry for any confusion. I answer mainly software questions, so in your initial question: "Today I Copy & Paste that old design and I can’t make the PORT0 /RTS pin to move", I took it to mean you copy and pasted software source code in your own custom application. So the statement “... out of the box - no programming or development is required” is true, I just didn't understand you were referring to copy and pasting a hardware design? Is that correct?

If you can put the same .s19 file in your other h/w and 485 works, and given that you did your tests to prove the rts signal can toggle, I am not quite sure why it would not work in 485 mode. Maybe lift the rts pin so it isn't connected to anything, then look at it on the scope when you make a serial transmission.

[LYN]

I Tom,

Sorry for the copy & paste confusion and I don’t have access to my previous hardware design (see the IVD documentation).

1- I tried the “full” free RTS pin3.
1.1 no move in the RS-485 mode
1.2 When program in RS-232 mode with hardware flow control the pin goes to low level. And go back steady high in RS-485

2- In RS-232 mode I’m able to change the pin3 from RTS to a GPIO function.
2.1 Automatically when I program the serial mode to RS-485 the pin 3 goes back to RTS.
2.2 Previously I merely remember that I had to program that pin3 for the RS-485 and today version it is happening automatically!

3- The picture is my new design. The SBL2E is an important component.
3.1 I just want to make it work like a regular RS-485 to Ethernet converter!!!

Tank you for your time
Lyn

[TomNB]

Hello Lyn,

I have tested the device in RS-485 half duplex mode and it is working properly. I took a video of the operation and it is at the link below. The setup is as shown in the picture below. The video shows the configuration, data sent from the network to serial RS-485, and serial data from RS-485 to the network.

In the picture you can see the RS-485 signals from the J5 header of the eval board connected to the RS-485 inputs of an off the shelf 485 to 232 converter. The RS-232 is then connected to the computer comm port 4 running the MTTTY serial terminal program.

This test is running firmware 1.65. We also ran it with 1.68 and the results were identical.

The video link is: https://youtu.be/gXVF_1_-7fk

[LYN]

HI Tom,

Thank you very much for you support.

Well you are right. The SBL2E is working correctly in RS-485 and my RTS pin is OK!. But don’t discard your setup yet.

With your same setup try to go in the command mode (“+++” whit or without the TCI/IP connection). Now you are blind, your command will pass but you will not see the answer since the RST pin doesn’t work in the command mode. In my setup I have a second com port (3V TTL on TX pin1) to confirm that the command mode is responding correctly to the “+++”.

1- Yes I should have try the TCP/IP communication before but my problem is still there.

My project is to build an intelligent IOT gateway. The gateway task is to redirect communication to different server (mail, data, cloud…). To do that it’s imperative to control the IP address and the outgoing connection through the command mode...

2- Using the second port is NOT an elegant solution since my com port are “VERY” busy.
3- Please could you confirm my point about the Control pin3 (in control mode)
4- If it is confirm, is it a big deal to make it work?
5- In the meantime I will continue my development (with my pseudo RX) and test all those different command.

Thank you
Lyn

[TomNB]

Hello Lyn,

Thank you for narrowing it down to command mode. That made working on this much easier. The attached beta will work with 485 half duplex in command mode. For a release version please contact NetBurner though support or sales.

[LYN]

HI Tom,

Thank you, I will let you know ASAP. I will look what I need to update the firmware and confident to find
everything in your documentation and web site.

Still have a lot to do but it is getting forward.

Lyn

[LYN]

HI Tom,
Thant was a nice update.
1- You demonstrate that you can do the modification and eventually make it perfect. BUT!
2- The RS-485 in command mode is producing ECHO. All character come back to me so I need to go very slow for not to have collision
3- The RS-485 in connect mode is working on one direction only!

I will let you take a look at it.
Please note that I don’t mind doing the testing. My setup is ready.

Thank you
Lyn