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Altera_Forum
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10 years ago

DIFFIO_TX_P/N versus DIFFIO_RX_P/N Cyclone V and others

Hi,

Can I use a DIFFIO_TX_P/N of a Cyclone V or other FPGAs as a LVDS input and vica versa?

Although there is written TX (transmit) and RX (receive) there is also written DIFFIO (=input/output).

Would like to use them for LVDS input.

Regards.

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    No. You can't use the 'DIFFIO_TX' pairs as LVDS input pins on Cyclone V. You can use 'DIFFIO_RX' pairs as emulated LVDS outputs. However, that's the extent of the flexibility.

    This differs from previous Cyclone families which offered more generic TX/RX pairs. E.g. Cyclone IV offers 'DIFFIO_xxp/n' pairs. These can be used as either input of output LVDS pairs.

    Cheers,

    Alex
  • Altera_Forum's avatar
    Altera_Forum
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    Hi Alex,

    thanks for your answer.

    But I beleive I can use DIFFIO_RX as sub_LVDS input to receive diff. data, can I?

    And DIFFIO_TX I can use as output (LVDS or single-ended) Am I right?

    Regards.

    ---------

    --- Quote Start ---

    No. You can't use the 'DIFFIO_TX' pairs as LVDS input pins on Cyclone V. You can use 'DIFFIO_RX' pairs as emulated LVDS outputs. However, that's the extent of the flexibility.

    This differs from previous Cyclone families which offered more generic TX/RX pairs. E.g. Cyclone IV offers 'DIFFIO_xxp/n' pairs. These can be used as either input of output LVDS pairs.

    Cheers,

    Alex

    --- Quote End ---

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    Correct. You can use 'DIFFIO_rx' pairs as sub-LVDS or LVDS input pairs and 'DIFFIO_tx' pairs as output pairs (or single ended outputs).

    You just can't use 'DIFFIO_tx' pairs as inputs.

    Cheers,

    Alex
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor

    Thanks Alex !

    --- Quote Start ---

    Correct. You can use 'DIFFIO_rx' pairs as sub-LVDS or LVDS input pairs and 'DIFFIO_tx' pairs as output pairs (or single ended outputs).

    You just can't use 'DIFFIO_tx' pairs as inputs.

    Cheers,

    Alex

    --- Quote End ---