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Altera_Forum
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15 years ago

Device selection

Hello,

I am looking for a simple glue logic solution that has about 4k D-flip flops. The glue logic just involve simple counters, shift registers, and combination logic. But I need very tight timing data for the logic such as setup time, hold time, etc. I found that the MAXII datasheet has very detail timing data, but the Cyclone FPGA datasheet does not show any detail. All I can see from its handbook is that it can go up to a few hundred MHZ. But the MAXII might not have enough gates for my purpose. I do not want to install any software on my PC until I am sure I want to go for a particular device.

I look at other competitors web site and similar things happen. Most CPLD datasheet provides detail timing, but most FPGA datasheet is very vague on timing information.

BR - Henry

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  • Altera_Forum's avatar
    Altera_Forum
    Icon for Honored Contributor rankHonored Contributor
    15 years ago

    Thanks for all your reply. We will most likely select the Cyclone IV device for this application. I believe good technical support is also a key factor in selection of devices, as I got no response from Lattice in both local sales and forum.

    After I read the datasheet carefully, there is a section in I/O Timing, and it mentioned that there is an Excel-based I/O Timing worksheet. Then I download the worksheet and looked at the devices. The worse case delay is (tsu + tco), which equate to a little higher than 100MHz for a C8 speed grade. So I think it should be okay. We will install the software and further verify this with simulation.

    BR - Henry