I understand that there is not enough bandwidth/GPIO pins to have both a second RAM chip and VGA output at the same time, but how hard would it be to create a board with a physical switch that either patches those pins to the second RAM chip, or the VGA output, depending on which way it's flipped? If it's not too hard to implement, I think this could be a best-of-both-worlds approach for people who regularly use simultaneous analog and digital output but would also occasionally like to utilize dual RAM for future cores that require it, like the upcoming new Midway cores. Is this approach at all practical?
Dual RAM switch for analog IO board?
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colonel panic
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Re: Dual RAM switch for analog IO board?
Here's a splitter. All you would need is to insert a switch somehow.
Re: Dual RAM switch for analog IO board?
One big problem with the DE/10 nano already is that it use a general pin socket for memory.
And the problem is that any connector on the way WILL degrade the signal (and make the traces longer that also will degrade the signal only a lot less then a connector), that will lead to not being able to run the ram at high speeds.
The memory chips and the FPGA could run at a much higher speed if no connector and short traces where used.
Adding a switch then you will have one more connector/even longer traces and a switch added to the path.
Depending what switch is used, like a mechanical switch that will most likely degrade the signal much,much,much more then the connector already does.
If a non mechanical switch is used that would be better but they will probably degrade the signal too but much less.
My guess!
And it is a BIG guess is that it will not be possible to run the memory at any useful speed, or at least it will most likely be very hit and miss.
And by hit and miss i mean if you get a very good stick of ram with very good memchips, very good connectors/switch and so on it could maybe work but if you get one part that is not top notch (but would work normally on the mister with one connector used) your probably screwed.