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LMH1219: LMH1219

Marcelo Hebling
Prodigy 80 points
Part Number: LMH1219
Other Parts Discussed in Thread: LMH1218,

Hello everyone

I'm develop a fiber optical to SDI bi-directional converter using LMH1219 as TX and LMH1218 as RX.

I wrote the code following the Programming Guide the both devices but the LMH1218 don't show the image that LMH1219 is received.

I would like to know if I can send the code snippet relating to the device settings so that you can analyze it and if there is an error you can help me correct it.

Can I to send?

Thanks

Marcelo

Alphacine

  • 0
    TI__Guru* 93670 points

    Hi Marcelo,

    Sure you can send this code snippet. Please include a block diagram as well.

    Regards, Nasser

  • 0 in reply to Nasser Mohammadi
    Prodigy 80 points

    Hi Nasser,

    Thank you for receive my inquire, above my code and block diagram.

    Code:

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    void Config_Chip_TX()//Rotina de configuração do chip conversor de fibra para SDI como TX
    {
    //Para operacao de escrita devemos colocar 0 antes do endereco
    //Para operacao de leitura devemos colocar 1 antes do endereco
    //---------Configuracoes------------------------------------------------
    /*habilita a pagina do registrador CTLE/CDR
    HAL_GPIO_WritePin(GPIOA, CS_1_Pin, 0);
    operacao_tx = 0x00;
    endereco_tx = 0xFF;
    dado_tx = 0x04;
    mascara_tx = 0x07;
    comando_tx = operacao_tx+endereco_tx+dado_tx+mascara_tx;
    HAL_SPI_Transmit(&hspi1, &comando_tx, 1, 100);
    HAL_GPIO_WritePin(GPIOA, CS_1_Pin, 1);
    HAL_Delay(100);*/
    //habilita a pagina do registrador CableEQ/Drivers
    HAL_GPIO_WritePin(GPIOA, CS_1_Pin, 0);
    operacao_tx = 0x00;
    endereco_tx = 0xFF;
    XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

    Regards, Marcelo

  • 0 in reply to Marcelo Hebling
    TI__Guru* 93670 points

    Hi Marcelo,

    A). Please allow me to make sure i understand this block diagram. LMH1219 has two 100-ohm high speed outputs. Why didn't we use one of these outputs and provide to LMH1218 100-ohm high speed inputs? Or perhaps LMH1218 high speed input is coming from the optical module receiver?

    B). Does LMH1219 shows lock indication? Registers above does not seem to show this?

    C)> The same for LMH1218. Please review LMH1218 programming guide and let us know cdr.0x03 content.

    D). Is it possible for you to use LMH1219 GUI? You can do this as long as you are using SMBus interface. GUI sets up the device as required. Also, GUI top level provides us with status of both LMH1219 and LMH1218 devices.

    Regards, Nasser 

  • 0 in reply to Nasser Mohammadi
    Prodigy 80 points

    Hi Nasser,

    I will try to answer your questions...

    A) The LMH1219 will receive the SDI signal send by an camera, for example, and delivered to a fiber optic transceiver to this send to another equipment video. However, the LMH1218 will be receive another signal by fiber optic transceiver provenience another equipment video and will delivery to the SDI Out to 3th equipment video work with this signal. Note that is the different signals to different pourposes.

    B) Yes, the LMH1219 shows lock indication when it has a signal in the input pins.

    C) The LMH1218 maintain the lock indication full time, independently if has or no signal to delivery.

    D)No, unfortunately no because I'm to use the prototype board to develop the firmware to configure this devices and change the communication method will cause the loss this boards and I will need to redraw the all project and I spandex more time with this project.

    Regards, Marcelo

  • 0 in reply to Marcelo Hebling
    TI__Expert 7440 points

    Hi Marcelo,

    Hope you're doing well, I'm going to assist with Nasser. 

    Marcelo Hebling said:
    C) The LMH1218 maintain the lock indication full time, independently if has or no signal to delivery.
    • How are you determining the lock indication? Are you using the LMH1218 EVM from TI? If so, you would be able to see the lock indication on the green LED D1. Otherwise a way to see it using SPI is to read the register cdr 0x02 and if the result is 5C then you are locked.
    Marcelo Hebling said:
    Note that is the different signals to different pourposes.
    • Are you using both the LMH devices in equalizer mode?
    Marcelo Hebling said:
    B) Yes, the LMH1219 shows lock indication when it has a signal in the input pins.
    • How are you able to see a lock indication?

    For further help in debugging the code please refer to this video on SPI: https://training.ti.com/spi-access-using-fpga-or-asic-using-lmh12xx-12g-sdi-devices

    Best,

    Nick