Programmable Devices
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20403 Discussions

Quesiton for Cyclone IV EP4CE15M9I7N design



There are some questions I still did not get the answer.



1) Bank 3 & 4 are used for DDR2 RAM. In each bank, there are two

reference pin VREFB3N0 & VREFB3N1. Just confirm only one pin should be

used as reference, the other one can be used as general IO, right ?


Answer -> Yes, one pin can be used as general IO. The usage depends upon which VREF group you are using. 

XSHEN -> What do mean depends on VREF group? I think you are talking about VREF is referred to its bank, right?


2) In the pin out list, there is dedicated pin for DDR2 DQS and CLK.

Just confirm any diferential IO at banck 3 & 4 can be used for DDR2 DQS

and CLK, right?


Answer -> Though the dedicated DQS pin is optional to use, please note that this pin drive the dedicated phase shift ciruitry which helps in fine tuning of the input strobe.

XSHEN -> I did not get the answer. My question is that any specified pin for DQS and CLK from FPGA side?


4) I use high speed ADC with LVDS output based on power supply = 1.8V.

But intel sepc requires FPGA LVDS IO VCCIO = 2.5V. Can connect it

drectly? DC couple?


Answer -> Please refer to this KDB article:

XSHEN -> OK, so the answer is yes.


6) MSEL0, MSEL1.... requires related VCCIO = 3.3V, right? So bank 2

VCCIO = 3.3V?


Answer -> MSEL pins should be connected to VCCA. The value of VCCA = 2.5V.

XSHEN - > OK. Can I assign bank 6 VCCIO = 1.8V and CONF_DONE pulled up to 1.8V ?


What's max power current for power supply VCCINT, VCCIO, VCCA, VCC_PLL?

Can I get this value from datasheet before doing any power analysis job

for choose power supply?


Answer -> Use Early Power Estimator (EPE) tool to estimate the power. For more details and links, refer: 

XQSHEN - > I know EPE tools. But the marco in excel is too old to pen. It doesn't work and will stuck computer.

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5 Replies



Did you ask these questions based on previous post? May I get the link of that post to understand this case better?


Thank you

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Vref means voltage reference. You can also refer to the pinout file for FPGA on your inquiries: question:


You can refer on page 265 from this link Cyclone IV Device Handbook that get those values. 


Are you able to use the latest version of Excel to open EPE tool?






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Is there any update on your end? I will close this case in 3 days if there is no update from you.


Thank you

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 We do not receive any response from you to the previous question/reply/answer that I have provided. This thread will be transitioned to community support. If you have a new question, feel free to open a new thread to get the support from Intel experts. Otherwise, the community users will continue to help you on this thread. Thank you.

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