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Altera_Forum's avatar
Altera_Forum
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17 years ago

Max II - to - Cyclone III questions

I have successfully used the Max II (144-pin TQFP) in a PCI-interface design and am designing designing a Cyclone III C40 (QTFP-240 pin) -based upgrade. After trying to absorb as much of the Altera literature, and reading this and other forums, I still have some potentially simple questions.

1) Can the Cyclone III C40 handle the 33 MHz, target-only PCI speed? All indications are true, but I was wondering if anybody else has done a PCI design using the slower Cy III quad pack chip.

2) What are suggested vendor/type diodes used in the AS (Active Serial) line interface shown in the Cyclone III Device Handbook, Volume 1, July 2007, page 10-56 reference design?

3) If all programming is done through an AP (Active Serial) 10-pin interface, what is the benefit of having a JTAG connector on the new design? (This assumes that the Serial Flash Loader option is not chosen... but perhaps it works well enough in a production environment that it should be considered rather than the AP.)

Comments/suggestions/experienced ridicule are appreciated...

Bruce

Bruce Ray

Wild Hare Computer Systems, Inc.

4 Replies

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    @2) I think, Schottky signal diodes are generally preferable. e.g. BAS40, BAR43

    @3) If you don't design dedicated development boards, debugging is a sufficient reason to install a JTAG interface, I think. Boundary scan option would be another. To my opinion, JTAG indirect programming is suitable for production purposes.
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    Thanks for the comments "FvM" -

    I'll check the various BAS940-type parts and form-factors to see what would work okay in the design.

    I think we can afford the board space to have both JTAG and AS 10-pin connectors on our initial Cyclone III-based design, so both will now be planned.

    Quartus 8.1 seems to use about 80 LEs for the Serial Flash Programmer MegaWizard Plugin code, so this is not a problem with our current design.

    The power requirements options are almost overwhelming as this is the "final" part of the design I'm reviewoing. Whether linear or LDO regulators for the +1.2 V VCCint and 2.5 V VCCpll and VCCa; 4-layer or 6-layer boards, and a few other items seem to be a part of the implementation balancing act.

    Bruce
  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    You can also temporarily load the Altera provided default SFL design, so SFL usage must not consume additional LEs at all. For initial programming, it would be the preferred method anyway.

  • Altera_Forum's avatar
    Altera_Forum
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    17 years ago

    A simple/stupid question...

    Can the LDO voltage regulators or the switching regulators be combined in

    parallel to get higher current output rating. That is, say we have a Linear

    Technology LT1117 rated at 1.5 A output, can we put two of them in parallel

    to get 3.0 A output? Likewise with parallel combination of same type of

    switching regulators?