FPGA, SoC, And CPLD Boards And Kits
FPGA Evaluation and Development Kits
Announcements
Intel Support hours are Monday-Fridays, 8am-5pm PST, except Holidays. Thanks to our community members who provide support during our down time or before we get to your questions. We appreciate you!

Need Forum Guidance? Click here
Search our FPGA Knowledge Articles here.
5241 Discussions

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

Lambert
New Contributor I
367 Views

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 have try once using the method, but It has error. Who can provide me one example about Emulated LVDS output buffer ?

 

Best regards,

Lambert

0 Kudos
5 Replies
Rahul_S_Intel1
Employee
152 Views

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
New Contributor I
152 Views

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

Rahul_S_Intel1
Employee
152 Views

Hi Lambert,

To be frank, I did not done an design with Altera LVDS block and Altiobuff. So I am not in a position to commend on the use case . One more thing I notices is that the file mentioned is SDC file, Can you please assign the above statement in qsf file.

 

 

Lambert
New Contributor I
152 Views

Hi RSree,

I think the problem does not depend on the file of pins assignments, and I think I face some special thing which needs to do when implement Emulated output buffer, if you have one simple case which you implementa the Emulated output buffer, it may give me a hand and let me find the error. Because I have no example to do this thing though I have serched for many files and website. There is less tips in Handbook.

Best regards,

Lambert​

Rahul_S_Intel1
Employee
152 Views

Hi Lambert,

From my side, I do not have any reference design

Reply