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Multiple foot print with Diptrace — Parallax Forums

Multiple foot print with Diptrace

max72max72 Posts: 1,155
edited 2011-02-05 14:09 in General Discussion
I'm creating a circuit based on the propeller and on Diptrace.
At schematic level I can choose DIP or SMD version of the propeller, but footprint and connectivity changes a lot and it is necessary to heavily modify the schematic.
Is there an obvious way to have the double option? For instance at the moment I'm working with the DIP version. In case I'll find the package is too big, or I feel still handed, I would like to switch to an SMD version. I would like to be able to start a new layout simply changing footprint, but not modifying the schematic. Is it possible? Maybe with a sub circuit, or in a so obvious way that nonetheless eludes me?
Thanks in advance,
Massimo

Comments

  • LeonLeon Posts: 7,620
    edited 2011-02-05 06:13
    With most PCB packages you have to make the QFP version a different part and Diptrace is probably similar. If the SMD footprint matched the DIP version in terms of pin functions, or you were switching between QFP and QFN packages, it wouldn't be necessary, of course.
  • max72max72 Posts: 1,155
    edited 2011-02-05 06:20
    Thanks for the answer.
    DIP and QFP are rather different. Mainly pin mapping and number of power supply pins.
    I'm wondering if it would be possible to create two subcircuits, with the same external interface, and inside the different pin number and mapping?
    Maybe in the subcircuit I could add 2 or 4 decoupling capacitors, depending on the package..
    Massimo
  • LeonLeon Posts: 7,620
    edited 2011-02-05 06:31
    I can do that with the Pulsonix software I use as it has hierarchical design. I don't know if it can be done with Diptrace, though.
  • max72max72 Posts: 1,155
    edited 2011-02-05 06:38
    I have to investigate if with Diptrace it is possible. Anyway do you consider the subcircuit solution feasible? I'm wondering if I'm missing something obvious here.
    Thanks,
    Massimo
  • LeonLeon Posts: 7,620
    edited 2011-02-05 06:41
    It should work. It would be much simpler to just create two different parts and use them as appropriate, though,in different PCB designs.
  • WBA ConsultingWBA Consulting Posts: 2,935
    edited 2011-02-05 10:08
    I don't know if that is possible or not, but between the QFP and DIP there are differences schematically so I could see why you couldn't. (The QFP has four more pins that need to be defined)
  • novarmnovarm Posts: 17
    edited 2011-02-05 10:50
    1. In DipTrace you can use subcircuits connected to main circuit by net-ports, changing subcircuits in this case will be only renaming main net-port (for example you can name subcircuit ports: DIP and QFP and if net-port on the main schematic will be DIP, it will be connected to DIP, if QFP - to QFP). In this case carefully check pin names (it is better to display them and give the same name as on the chip) - pins with similar names are connected. See how to work with net-ports in tutorial.

    2. Another way is making 2 hierarchy sheets. In this case you will need to replace blocks - there is sence to make similar pin arrangement in blocks for easy replacement. I would recommend the first way as much easier and obvious though.
  • max72max72 Posts: 1,155
    edited 2011-02-05 14:09
    Thanks,
    I'll check the tutorials and play with both solutions.
    Massimo
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