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Enabling the timestamp function on the ADC12J4000EVM

Maxime Drouguet
Prodigy 30 points
Other Parts Discussed in Thread: LMX2581, ADC12J4000EVM, ADC12J4000

Dear Sir/Madam

I'm working with the ADC12J4000EVM (the former version, with the LMX2581 Synthesizer) and the TSW14J56 (rev B). I use external clocking to reach 4GSPS and up to there everithing work fine.

I want to use the TimeStamp feature but when I remove R19 and R20 in order to connect the timestamp SMAs, I always got a time out error in HSDC (v4.1). However in the ADC12J4000EVM GUI (v1.3 but in Help\about it says v1.0) enabling the timestamp or not and toggeling the Single-Ended SYNC~ select doesn't help.
NB : I didn't connect anything yet to the Timestamp SMAs since the ADC12J4000 datasheet says that those pins can be left unconnected if unused.

Could you help me to use the single ended SYNC~ pin to provide JESD synchronization in order to release the SYNC~/TMST pins for timestamp function ?

Yours sincerely

Maxime D.

  • 0
    TI__Mastermind 44680 points

    Hi Maxime

    I'm working on this and will have a response later today.

    Best regards,

    Jim B

  • 0 in reply to Jim Brinkhurst1
    TI__Mastermind 44680 points

    Hi Maxime

    To enable the Timestamp function on that revision of EVM, please do the following:

    1)      In the Low Level View tab, locate the ADC12J4000 register 0x202h and change bit 6 from 1 to 0. This changes the SYNC~ input from differential to single ended. I think the button on the high level tab is not correctly linked to the correct bit. This is hopefully the issue you ran into.

    2)      In the Low Level View tab, locate the ADC12J4000 register 0x050h and change bit 5 from 0 to 1. This enables the timestamp feature. The high level button for this may be working correctly but this will ensure everything is set up.

    As you noted, resistors R19 and R20 must be removed. Did you also install the 0 ohm resistors R18 and R21?

    If captures now work, the lsb of the 12 bit data will be showing the logic state of the TMST+/- differential inputs. The easiest way to see the LSB in isolation in High Speed Data Converter Pro is to switch to the Time Domain mode in the Test Selection pull-down, and then change the display window from Codes to Bits.

    If the steps above don't help please let me know.

    Regards,

    Jim B

  • 0 in reply to Jim Brinkhurst1
    Prodigy 30 points
    Wrong linking of the Bit 6 in register 0x202h was the problem. It's working fine now. And timestamping too.

    Thanks a lot !

    Maxime D.