Working/Not Working???

Hi John,

The ADM232LJR is a 2Tx/2Rx rs232 transceiver so it takes care the signal transmission. As long as the signal package is the same, it should transmit and receive the same information. I can help to verify whether ADM232LJR operates normally if you can provide a schematic and waveform picture for its input T_IN_/R_IN and output T_OUT/R_OUT pins. If you are able to observe waveforms on TX and RX pins (commands you send out and receive), you can compare the signals whether they are identical with different codes.

Best,

Jane

Hi Jane, thanks for the reply!

Attached is the schematic.  Any waveforms you wish to see, I will have to clear the bench and attempt to capture them.  The TDS 540 is getting long in the tooth as I.  In the schematic, I highlighted the UART in yellow.  As you can see, it is as vanilla as it can be.

I did omit in my original post that after I replaced the backup battery (CR3022) and it died a couple days ago (less than a month).  On the schematic, it exactly left to the UART and feeds the microprocessor's 5V line.  It also goes off to another board which I have yet to identify (thanks to the crummy service manual), so I guess I'll have to open it again and ID the ribbon cable.

In any event, maybe from the print, you could give some insight.  If it weren't for the original bad UART and the 3-week dead battery I would say it is my programming, but now I wonder...

Thanks again!

John

Hi John,

The schematic is not legible. Is it possible to zone into the ADM232LJR/AMD232L? I can point out where you can check and verify whether the part operates properly.

Best,

Jane

Hi Jane, sorry for the delay.

Hopefully this image will be better.  I don't know why I sent you the whole page.  This one contains the UART, DB-9, and microprocessor.

I appreciate your interest in pointing me in the right direction.

Thanks,

John

Hi John,

The schematic is still not clear, but I think I can figure out the signal flow with ADM232LJR. It looks like two drivers and one receiver are connected. Before checking on the signal, please verify voltages on pin 2 (V+) and pin 6 (-V) of the ADM232LJR. They should be >= +/-5V (+/- 9V typ.) If both voltages are in the correct range, the drivers should work properly. CAT TX (UART, pin 3) is the input of the driver channel 1 at pin 11 (CS0). The output of driver channel 1 at pin 14 connects to TX on DB 9 connector. Channel 2’s output (pin 7) goes to CTS on DB9 connection. RX signal on DB 9 connector goes to pin 13 (RIN) of the ADM232LJR. To verify your code, you could monitor the data stream at the output of the receiver pin 12 (CS1) or pin 8 CAT RX (at UART’s input).

Best,

Jane

Hi Jane, sorry for the delay.  I'm trying to get ready for a boatload of people for the 4th...

The UART works with an exe written in QT/C++ , taking a command to do something (this command does not return anything).  Strange thing with this code, is it never works on first click, but works every time thereafter - as long as the exe remains open.  It does not keep the port open though as I can access it with the exe GUI still open.  I did not write it.

I have 1 LabVIEW and 4 versions of Python code that does not work.

Problem is, if I connect the sending COM port to a receiving COM port, code I wrote to read the receiving buffer and opened before sending the command returns the same # of bytes and exactly the same command no matter what code is sent (including the working code).

The plan is to put a scope on the UART and capture what works and what does not.  I'll let you know.  Enjoy the Holiday!

Thanks,

John