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Altera_Forum's avatar
Altera_Forum
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15 years ago

Error: Can't place differential I/O negative pin mem_dqs[0] at a differential I/O pos

When I compile my own DDR3 ctrl, the errors show like below:

error: can't place differential i/o negative pin mem_dqs[0] at a differential i/o positive location d29(pad_1046)

error: can't place differential i/o negative pin mem_dqs[1] at a differential i/o positive location c31(pad_1058)

error: can't place differential i/o negative pin mem_dqs[2] at a differential i/o positive location b34(pad_1070)

error: can't place differential i/o negative pin mem_dqs[3] at a differential i/o positive location e33(pad_1082)

error: can't place differential i/o positive pin mem_dqsn[0] at a differential i/o negative location c29(pad_1047)

error: can't place differential i/o positive pin mem_dqsn[1] at a differential i/o negative location b31(pad_1059)

error: can't place differential i/o positive pin mem_dqsn[2] at a differential i/o negative location a34(pad_1071)

error: can't place differential i/o positive pin mem_dqsn[3] at a differential i/o negative location d33(pad_1083)

In fact, i use the script below to tell quartus that mem_dqs[0] is the positive pin, but quartus still infers as a negative pin.

set_instance_assignment -name dqsb_dqs_pair on -from mem_dqns[0] -to mem_dqs[0]

Could someone help me?

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    --- Quote Start ---

    -from mem_dqns[0] -to mem_dqs[0]

    --- Quote End ---

    Isn't there a spelling error?
  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    I experienced similar problem... by tracking back to the design files, look into where the OBAR, IBAR, and IOBAR (negative ports) helped me find out where the tool pick up the wrong polarity.

  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    13 years ago

    I presume you've already run <core_name>_p0_pin_assignments.tcl TCL script ?

    It adds some annotations to QSF.

    Otherwise, you'd see some weird errors.

    Thanks,

    Evgeni