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Lambert's avatar
Lambert
Icon for Occasional Contributor rankOccasional Contributor
6 years ago

How to implement Emulated LVDS OUTPUT buffers? Who can provide me one example?

Hello everyone, Recently, I want to use the Emulated LVDS output on Arria V device. But I have no idea how to implement it ? Just to use Altera_tx IP + ALTIOBUF IP + Output Resistor Network? I hav...
Rahul_S_Intel1's avatar
Rahul_S_Intel1
Icon for Frequent Contributor rankFrequent Contributor
6 years ago

Hi Lambert,

Kindly find the transcript from the user guide to perform Emulated LVDS OUTPUT buffers .

Emulated LVDS Buffers in Arria V Devices The Arria V device family supports emulated LVDS: • You can use unutilized true LVDS input channels as emulated LVDS output buffers (eTX) for serializa‐ tion factors of 1 and 2. • The emulated differential output buffers support tri-state capability

  • Lambert's avatar
    Lambert
    Icon for Occasional Contributor rankOccasional Contributor
    6 years ago

    Hi RSree,

    I have read that you said "Emulated LVDS Buffers In Arria V Device Handbook " previously. And I tried to use ALTLVDS_TX IP + ALTIOBUF + External resistor network to implement eTX.

    Code likes this (one) :

    altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));

    altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o));

    altiobuf altiobuf_u1(.data_in(tx_out),.oe(1'b1),.data_out(tx_out_n));

    assign tx_out_n_o = ~tx_out_n;

    ​

    SDC like this:

    set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o

    set_instance_assignment -name IO_STANDARN LVDS_E_3R -to tx_out_n_o

    set_location_assignment PIN_A23 -to "tx_out_o"

    set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)

    this method has error when I compile code.

    ​

    the code (two):

    altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));

    altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o), .data_out_b(tx_out_n_o));

    ​SDC like this:

    set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o

    set_location_assignment PIN_A23 -to "tx_out_o"

    # set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)

    this method has error when I compile code.

    ​

    the code (three)

    altlvds_tx altlvds_tx_u(.tx_in(a), .tx_inclk(clk), .tx_enalbe(load_en), .tx_out(tx_out));

    altiobuf altiobuf_u(.data_in(tx_out), .oe(1'b1), .data_out(tx_out_o));

    altiobuf altiobuf_u1(.data_in(tx_out),.oe(1'b1),.data_out(tx_out_n));

    assign tx_out_n_o = ~tx_out_n;

    ​

    SDC like this:

    # set_instance_assignment -name IO_STANDARD LVDS_E_3R -to tx_out_o

    #set_instance_assignment -name IO_STANDARN LVDS_E_3R -to tx_out_n_o

    set_location_assignment PIN_A23 -to "tx_out_o"

    set_location_assignment PIN_A24 -to "tx_out_n_o" (assuming A23 and A24 for DIFFIO_RX)

    this method has error when I compile code.

    So I don't know how to implement it , and I can not find one example and have no idea. I need help to resolve this problem. Can you help me?

    Thanks,

    Lambert