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MinzhiWang's avatar
MinzhiWang
Icon for Occasional Contributor rankOccasional Contributor
11 days ago

FPGA resource issue of Cyclone 10 GX devices

Hello Guys,

We used 10CX220F780 before. Now one of our new application will switch to use 10CX105F780. Because both of them are package compatible, we only need to check some special logic physical constrains.

Our question is that their chipplanners show us same pages. However, 105 and 220 should have half difference at least. We checked that they have same x-coordinate and y-coordinate. So they have same counts of LAB resources, why?

 

Best Regard

 

Core Logic

2 Replies

  • FakhrulA_altera's avatar
    FakhrulA_altera
    Icon for Regular Contributor rankRegular Contributor
    4 days ago

    Hi,

    What you are seeing is expected. The 10CX105F780 and 10CX220F780 use the same F780 package plan, so the Chip Planner can show a very similar floorplan and similar X/Y locations. This is mainly for package compatibility and migration support. Refer: Cyclone 10 GX Package Plan, Cyclone 10 GX Device Overview

    However, their usable device resources are different. For example, 10CX105 has about 104K LEs / 38,000 ALMs, while 10CX220 has about 220K LEs / 80,330 ALMs. So even if the Chip Planner view looks similar, the actual available logic capacity is not the same. Check, Cyclone 10 GX Maximum Resources & Cyclone® 10 GX FPGA Product Table
     
    For resource comparison, please refer to the Fitter Resource Usage report or the official device resource tables, instead of only the Chip Planner display. Also, please make sure the correct target device is selected and run a full recompile after changing the device. 

    You may refer to:


    Regards.
    Fakhrul

    • MinzhiWang's avatar
      MinzhiWang
      Icon for Occasional Contributor rankOccasional Contributor
      1 hour ago

      Hi Fakhrul,

      The above messages I can get from datasheet. However, the doubt I have is why they have same LAB numbers? According to the same X/Y locations, I think they have same LAB numbers. Please help to explain about this.

       

      In our application cases, we wanted to constrain some nodes to specified physical LAB locations. So when we switch from 10CX220F780 to 10CX105F780 we are afraid to use those unavailable LAB resources.

       

      As you said, 10CX220 has about 80330 ALM and 10CX105 only has 38000 ALM. So they should have twice difference. We also have 50% chance to touch those unusable LABs?

      Thanks