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LMH0318: LMH0318 Signal Detect failure

Giuseppe Lippolis
Prodigy 40 points

Part Number: LMH0318

Hallo All,

I'm using the LMH0318 driven by the FPGA.

The video reclocking feature is working.

I'm also configured the device in IRQ mode (on LOS pin) to monitor the status of the device.

I'm performing a test to validate the monitor function. During this test I'm disabling the SDI stream in the FPGA and then I re enable it.

Often I get the expected behaviour: as soon as the stream is disabled, I got an IRQ and the Interrupt Status Registe (0x54) reports 0x05, this means "Signal Detect de-asserted, cdr_lock_loss_int, signal_det0_loss_int".

But sometimes (~8%) I get a different results from the Interrupt Status Registe: 0x84, this means "Signal Detect asserted, cdr_lock_loss_int". It seams that sometimes the signal detector fails to detect the loss of signal.

I also try with different setting on the Signal Detect Threshold Setting (regs 0x14 and 0x15), but nothing change.

Do you have a tips to help me to understand that topics?

I'm looking forward to hearing from you.

Best Regards

 

 

  • 0
    TI__Mastermind 26771 points

    Hi, 

    Since interrupt registers are only cleared on read, it may have been the case that the interrupt register wasn't cleared. Have you tried reading the register multiple times? Also, have you seen any functional issue from this? Also could you check if this register correctly reflects the loss status?


    Best,
    J