Discussion in 'Wireless & RF Design' started by sidh447, Nov 20, 2013.

  1. sidh447

    Thread Starter New Member

    Nov 20, 2013
    I am using EVB HART MODEM QFN and facing the issue of loopback after connecting it to UART.Is there any solution to this??

    At present I am using single modem and getting the correct wave forms for transmitter which means that there is no issue with the Transmission side but we want to do the loopback and check the receiver as we are not getting any data on receiver side.

    Since we have not connected anything to the evaluation board and just evaluating the HART evaluation board by doing loop back only.I mean checking the communication of Evaluation board only.

    Is it possible to have a loopback with the single modem or we require more than one modems for it?

    Connections that we have made are :-

    1.From PC we have connected USB to TTL converter.

    2.From TTL converter we are connecting Signals like Rx,Tx,RTS,Vcc and GND(all parameters are for IDC1).

    3.We shorted two pins TxA and RxA(that belongs to IDC 2,pin no 7 and 3)

    In Terminal Emulator we have selected BAUD rate-1200,PARITY-EVEN,Handshaking-RTS on Tx.

    Secondly for sample master implementation they have specified OPAMP U1(Page no 17 in attachment) but there is no part number for it so I need that part number.

    Sidharth Khera
  2. gootee

    Senior Member

    Apr 24, 2007
    I am not an expert, but...

    if you have Rx and Tx connected, maybe it's a handshaking problem. Is there a CTS? Or can you try Xon/Xoff (software handshaking) mode, instead of hardware (RTS/CTS) handshaking?

    Check the AT commands list. You might have to issue some special AT commands to initiate loopback mode and testing.

    Why do you have Parity engaged?