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Hi All,
I am dealing with the pin assignments specifications for Altera's Cyclone IV FPGA. I am using Altera's Quartus II software and using its QSYS tool I have designed a system to interface DDR2 SDRAM with FPGA. While I was assigning pin assignments to FPGA. I came across the feature - on-chip termination, which fascinated me as it can deduct the requirement of adding pull-up resistors and can reduce the bulkiness of the board. As all the pins from FPGA to SDRAM are output or bi-directional, I have applied output termination with series 50 ohms with calibration to all the pins. My questions are- 1.is my decision of applying output termination, with series 50 ohms calibration, to bi-directional pins correct? (I have read that For input pins, input termination should be used with parallel resistors For output pins output termination should be used with series resistors For bi-directional both the input and output termination or dynamic termination should be used. But in Cyclone IV input termination and dynamic termination options are not available. These options are there in Stratix family FPGAs) 2. If output termination with series 5o ohm with calibration is correct, do i need to add any external resistors for termination on fpga side?(Except RUP and RDN resistors) Please don't misguide me if you are not sure about your answer. It may cause a very big trouble to my PCB department. It's better that you give some references so that I can clear some things in my mind about OCT. Thank you. Ashish DevreLink Copied
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