LMH1297: How to use EOM ?

user6478485

Part Number: LMH1297
Other Parts Discussed in Thread: SIGCONARCHITECT, USB2ANY

Hi, Teams.

I read the "LMH1297 Programming Guide" to use SPI Fast EOM Operation. It is purpose on monitoring waveform just prior to the CDR reclocker.

But I couldn't understand the procedure of EOM.

Actually, I'm not familiar with software operations. Therefore, I need details about the procedure of EOM.

Please, answer the following questions.

1. Do I need any software to do SPI Fast EOM Operation? (e.g. SigCon Architect )

2. Do I need any external tools to connect the PCB with LMH1297 mounted and the PC with SigCon Architect installed?

　Or, Just connect its with USB-Cable?

3.According to Step.7 in page.14 in the "LMH1297 Programming Guide", I need to repeat Steps 5 and 6 another 4095 times...

Do you have any ideas how to do it automatically?

4.Could you tell me procedure step by step how to use EOM by using SigCon Architect.

Sincerely

over 4 years ago

0 Nasser Mohammadi over 4 years ago

TI__Guru* 93670 points

Greetings,

Please note comments below:

1).You can use either SigconArchitect or use your FPGA or ASIC to read eye diagram. Additionally you can read two registers - CDR/CTLE Page Reg 0x27 and Reg 0x28 - to read horizontal and vertical eye openings.

2). For SigconArchitect, you need to use USB2ANY box, install USB2ANY software, and then connect SMBus interface to the device mounted on your pcb. Please below note additional information about USB2ANY box and software:

https://www.ti.com/tool/USB2ANY?keyMatch=USB2ANY&tisearch=Search-EN-everything&usecase=GPN

3). When using your FPGA or ASIC, you need to perform these steps 4095 times. If using SigconArchitect there is no need for this. There is a tab for Eye Monitor Page in SigconArchitect GUI. Once device is locked, you can capture the eye diagram - by pressing on single capture button - and GUI automatically captures and displays the eye diagram.

4). Please note #3 above. Once you install this software, this is easy to follow.

Regards,, Nasser

0 user6478485 over 4 years ago in reply to Nasser Mohammadi

Prodigy 70 points

Dear Nasser,

Thank you for your reply and inputs. I understood well.

For EOM, I have some questions additionally.

(1) Is EOM real-time processing ?

It means, Do I need to consider the time to perform these steps 4096 times when I use ASIC or FPGA to read eye diagram?

(2)Could you tell me procedure step by step how to use EOM by using ASIC or FPGA. (sample codes, informative suport forum etc.)

0 Nasser Mohammadi over 4 years ago in reply to user6478485

TI__Guru* 93670 points

Greetings,

1). Yes EOM is real time and data is not buffered.

2). Please use link below for step by step procedure to download eye diagram samples:

https://training.ti.com/reconstruct-eye-diagram-raw-data

Regards,, Nasser

0 user6478485 over 4 years ago in reply to Nasser Mohammadi

Prodigy 70 points

Dear Nasser,

For real time processing, I have a question additionally.

(1) According to a document on the page.11, does it need that data transmission time of ASIC is faster than 33usec/cell ?

https://www.google.co.jp/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwjalKby7IvtAhUCzIsBHR7VAj8QFjABegQIAhAC&url=https%3A%2F%2Fe2e.ti.com%2Fcfs-file%2F__key%2Fcommunityserver-discussions-components-files%2F138%2FEye-Opening-Monitor-Description.pdf&usg=AOvVaw1VxwqfsZuVivZQkDlh5-RU

0 Nasser Mohammadi over 4 years ago in reply to user6478485

TI__Guru* 93670 points

Greetings,

Yes your understanding is correct. Within 33uS we should read hit counts.

Regards,, Nasser

0 user6478485 over 4 years ago in reply to Nasser Mohammadi

Prodigy 70 points

Dear Nasser,

I understood it.

(1) Can Reg 0x2A be set 1~255(decimal) when I use USB2ANY to get eye diagram by SigCon Architect?

   I guess eye diagram is more accurate by being Reg 0x2A decreased but My MCU does not meet the condition that a command transmission time of my MCU    is faster than 33usec/cell. This means I can't set smaller than 0x30.
   So I'd like to use USB2 ANY if it can set 1~255(decimal) or 0x01~0xFF(Hex) at reg 0x2A.
   My target of the minimum time hit counts is 256*1(0x2A = 0x01) * (32/11.88Gbps) = 689nsec.

Sincerely

0 Nasser Mohammadi over 4 years ago in reply to user6478485

TI__Guru* 93670 points

Greetings,

GUI eye capture has been qualified using default setting for reg 0x2A - 0x30 value. Using other values, is not known.

Please note reg 0x2A is the length of time the device spends to capture eye hits. The higher the value of this register the better is the approximation of the eye diagram. Perhaps you can put a wait state in your MCU to capture eye diagram with 33uS eye hits capture time. This is the same as what GUI uses.

Regards,, Nasser

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LMH1297: How to use EOM ?