ML505 differential clock outputs doesn't work

[tklau]

I'm following "ML505/506/507 MIG Design Creation" to test a DDR2 design, but I found that even if I follow that document exactly to configure my ML505, when I switch on the board, I cannot read any signal from the differential outputs (J12 and J13) using a scope, and (hence?) the "phy_init_done" never goes high. Both pins read 1.19V. Am I missing anything?

My settings on the board are:

• J54: Connected
• SW6: 01001010 (for 200MHz LVDS output)
• SW3: 00010101
• Default CF card, default DDR2 RAM inserted

[tklau · Accepted solution]

Turns out that the measurement problem is related to my scope which cannot measure differential signal properly.

My ML505 works fine with the sample file (ml505_mig_design.zip).

Thread closed.