ADM2867E not giving the output data correctly

Hello, thanks for the detailed info on the problem. 

Can you confirm that the J3 0ohm jumper is connected, the J2 jumper is disconnected, and you are applying the DE/RE signal to the RE pin (RTS) of the Mikroebus connector? This will confirm that the signals you are observing on the oscilloscope are actually making it to the DE and RE pins of the ADM2867E. 

This board does not have any probe points for DE/RE , where are you taking the oscilloscope measurements from?

If this is confirmed, as the next step in the debug, I would recommend checking that the power supplies on the ADM2867E are all powered up correctly. 

Regards,

Neil

Hello Neil,

Thank you for replying
I am actually not using mikrobus connector, I am connecting directly to RE/DE from my microcontroller and I can probe it in my testing board.
The board itself has J2 disconnected, and J3 connected, I have confirmed that.

Power supply should be correctly applied since actually there is 3.3V on the A B side, this is according to the power supplied at VCC 3.3V.
If you see the picture, the problem is AB does not give correct binary data like the TX, instead it just stay at that voltage (A high, B low) when TX sends data

Hello Neil,

Thank you for replying
I am actually not using mikrobus connector, I am connecting directly to RE/DE from my microcontroller and I can probe it in my testing board.
The board itself has J2 disconnected, and J3 connected, I have confirmed that.

Power supply should be correctly applied since actually there is 3.3V on the A B side, this is according to the power supplied at VCC 3.3V.
If you see the picture, the problem is AB does not give correct binary data like the TX, instead it just stay at that voltage (A high, B low) when TX sends data

Thanks for your reply,

I have tested an MikroE board here today and it appears to be working correctly. 

I'm not clear on what the cause of this issue is, though I agree that from your oscilloscope plots the A and B outputs appear not to be responding correctly to the TxD input. 

I would recommend a few steps to ensure the measurement setup is correct, 

• Have you measured 3.3V power supply on the AB side with a DMM or an oscilloscope probe? As you have mentioned, as VCC is 3.3V, then VISO should equal 3.3V, but it is still worth confirming this with lab equipment
• I would recommend taking all measurements if possible on the board rather than on the microcontroller board. For example, if there is an issue with the ground lead connection between your MCU board and the MikroE board, the signals measured on the MCU board do not reflect what is seen by the ADM2867E

Regards,

Neil