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I am absolutely new to FPGA devices, so please excuse me for novice questions.
I am designing a FPGA board using EP1C12Q240C8 of cyclone 1 device. I am using orcad capture for designing the schematic. I found this particular library for this model from Altera site. Now the problem is, in this model, there are 60 pins on each side of the FPGA, but in the orcad library given by altera, the pins are arranged haphazardly, not like the original device. I have attached a screenshot of the orcad library image. please help me.Link Copied
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I think, the pin arrangement in the schematic symbol is well considered, as far as possible in a single symbol.
I don't understand what's your actual problem with the pin assignment. I guess you already noticed that schematic symbol pins are ussually placed according to their function rather than to the package pin position?- Mark as New
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Finally i want to develop a pcb from the schematic design, so if i make the schematic given by altera , wont it be faulty if i convert it to pcb?
that's why i want a library with correct pin configuration. do you see my point sir? please help!- Mark as New
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No, I don't see your point, I presume a misunderstanding. As far as I see, the Orcad symbol shows correct pin numbers for EP1C12Q240, isn't it?
The position of pins at the schematic symbol hasn't to do with package pin position.- Mark as New
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--- Quote Start --- No, I don't see your point, I presume a misunderstanding. As far as I see, the Orcad symbol shows correct pin numbers for EP1C12Q240, isn't it? The position of pins at the schematic symbol hasn't to do with package pin position. --- Quote End --- But sir when a will change my schematic to PCB, it would be faulty isn't it??? or am I missing something?
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I don't understand the problem. Perhaps you should make a simple tests, connect a few signal pins and necessary power supply and configuration pins in schematic, transfer to PCB and review how the physical pins are connected in the layout view.
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--- Quote Start --- But sir when a will change my schematic to PCB, it would be faulty isn't it??? or am I missing something? --- Quote End --- The pin _number_ tells the PCB package which of the pins to connect the net to, not the position in the schematic editor. Nial
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What you see in Orcad Capture is the "Schematic" model of the device. Pins can be placed anywhere on the graphic, and it doesn't matter as long as the associated pin number is correct. Most schematic models group the pins by function (Power supply, individual gates, busses etc).
When you go to roll the board in your PCB editor of choice, you will load in a "Footprint" model of the device, which is completely different than the schematic model. This model is the actual positioning of the pins for the package that you choose for the footprint. Anything tied to Pin 1 on your schematic diagram, gets routed to pin 1 of the footprint.
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