UPGRADE YOUR BROWSER

We have detected your current browser version is not the latest one. Xilinx.com uses the latest web technologies to bring you the best online experience possible. Please upgrade to a Xilinx.com supported browser:Chrome, Firefox, Internet Explorer 11, Safari. Thank you!

Reply

ZCU104 - PL DDR4 address pins asignment

Accepted Solution Solved
Highlighted
Observer
Posts: 14
Registered: ‎06-21-2018
Accepted Solution

ZCU104 - PL DDR4 address pins asignment

Hello,

 

I am using a DDR4 SDRAM (MIG) controller where I defined the following pre-included memory part: MT40A512M8HX-093. The problem is that I get a 17-bit address bus (I suppose the bus width is included in the part definition), but the board uses just 14 bits [A0..A13]. I did not find any option to restrict the address bus to 14 bits so I am wondering what I should do with the upper bits. Should I tie them to ground? I tied them to some FMC pins just to get rid of implementation errors, but I am pretty sure there must be a better solution.

 

Thanks in advance and best regards,

Javichu


Accepted Solutions
Posts: 270
Registered: ‎02-11-2014

Re: ZCU104 - PL DDR4 address pins asignment

Hello @javichu,

 

You need all 17-bits of the address bus. A0-A13 are reserved specifically for A0-A13. But A14-A16 will be used for RAS/CAS/WE, specifically in your scenario A14 = WE_N, A15 = CAN_N and A16 = RAS_N. You should not tie these to ground.

 

Thanks,

Cory

-------------------------------------------------------------------------
Don’t forget to reply, kudo, and accept as solution.
-------------------------------------------------------------------------

View solution in original post


All Replies
Posts: 270
Registered: ‎02-11-2014

Re: ZCU104 - PL DDR4 address pins asignment

Hello @javichu,

 

You need all 17-bits of the address bus. A0-A13 are reserved specifically for A0-A13. But A14-A16 will be used for RAS/CAS/WE, specifically in your scenario A14 = WE_N, A15 = CAN_N and A16 = RAS_N. You should not tie these to ground.

 

Thanks,

Cory

-------------------------------------------------------------------------
Don’t forget to reply, kudo, and accept as solution.
-------------------------------------------------------------------------