LMH0340: Can LMH0340 support 1080p30 and 1080p25?

Hi Luck,

LMH0340/LMH0341 require external FPGA to implement different SMPTE frame rates. LMH0340/0341 provide superior analog performance while FPGA implements SMPTE higher layer protocols. So in summary, FPGA 1080p30 or 1080p25 frame rate support is done by the FPGA IP and LMH0340/LMH0341 does support electrical interface for these frame rates.

Regards,,nasser

Dears Nasser:

Thanks for your reply, however, the diagram of the project is below picture:

And the CPU is not FPGA, and a MCU, since LHM0030 has not industrial temperature, we are evaluating LHM0340.

Can LHM0340 support  1080p30 or 1080p25 based MCU?

Pls. kindly help us!

Thanks a lot!

Best regards

Luck Wu

Hi Nasser:

Thanks for your reply, and there are 3 issues to discussed with you:

1. We do not use FPGA and use STM32F030(MCU) which control the LMH0340's SMBUS. Is it OK for using MCU and not FPGA?

2. If we do not use FPGA, how can we design the code or set parameters to support 1080P30 or 1080P25 using MCU?

3. From our datasheet we can design our circuit, however, could you kindly help to give some suggestion to protect SDI Output for avoiding the electrical surge or other issues?

Thanks a lot!

Best regards

Luck Wu

Dears:

Now we are evaluating the LMH0340 AND LMH0040 which belong to your company. Since our evaluating process, we have met some questions which we need to confirm.Our system diagram is as below.

Our questions are :

1. Part 1(red circle marked 1): CAMERA will supply LVDS signals,but the signals are only 4 pairs TX plus pair TCLK.

   And the LMH0340 AND LMH0040 need 5 pairs TX plus pair TCLK. How can we connect them together ?

   Remark: The LVDS pairs of Our camera are : (TX0+,TX0-),(TX1+,TX1-),(TX2+,TX2-),(TX3+,TX3-),(TCLK+,TCLK-).

           LMH0340 LVDS pairs are  : (TX0+,TX0-),(TX1+,TX1-),(TX2+,TX2-),(TX3+,TX3-),(TX4+,TX4-),(TCLK+,TCLK-).

2.Part 2(red circle marked 2): MCU will be responible for comunication with LMH0340 AND LMH0040 via the SMBus bus.

  The MCU we used may be STM32F030(or STM8S103) and it will set some parameters to LMH0340 OR LMH0040. Now we have 

  a such demand that when CAMERA is set 1080p 25fps OR 1080p 30fps ,how can we set the registers of LMH0340 OR LMH0040, 

  as which it will match the CAMERA's video format. Please give me a datasheet or suggestions.

  Our solution shall not use FPGA but a MCU chip instead. All information about FPGA will not help us. Look forward your reply.

Best regards

Luck Wu

Hi Luck,

LMH0340 and LMH0341 were designed such that we MUST have FPGA to do SDI IP and close control of LMH0340/LMH0341 functions. LMH0340/341 do not have the functionality to frame LVDS data into the serial digital streams. So having a FPGA for LMH0340/LMH0341 is a must.

Please take a look at DS92LV0421 and DS92LV0422 since these devices may better be suited for your requirements. Please below note link to this data sheet:
www.ti.com/.../ds92lv0421.pdf

Regards,,nasser

Dear Nasser:

We have read the data sheet about DS92LV0421 and we think it may not be suitable for us. The reasons are as follows.

    1. DS92LV0421 must use in pairs with DS92LV0422, but our camera may connect many  kinds of SDI DVRs producted by other manufacturers.

    2. DS92LV0421 Output level is not suitable for our requirement. Our camera will drive coaxial cable but not STP cable.

    3. We don't find the transmission standard which DS92LV0421 confirms such as SMPTE-296M.

    Somthing else, we still have a question about LMH0340. Can LMH0340 detect video format like 1080P/25fps,1080P/30fps automatically ? If our camera can supply these videos, can LMH0340 recognise it and encode it to SDI output successfully ? 

    The last one, if not satisfy above, anything else integrated chip on SDI function can be given ? 

    Figure below is the usage in actually project.Red frame section is the entire device we producted. Thank you very much !

Best regrds

Luck Wu