So is this a AD7667 or AD7622 footprint? I found an AD7667 symbol and footprint on SnapEDA, which seems ok. I need to check it, but I have already imported it into my global libraries.
I found that when I did the display (first attempt in KiCAD) that I didn't model the mounting holes, but instead embedded them in the board itself. It worked, but a more flexible approach would be to model the pins and NPT mounting holes, so it would behave as a normal component. I may give that a try. Probably will seek advice on the KiCAD forum for that. I have a partial FreeCAD model for the display, that I could use as the start. I know the footprint and NPT holes worked on my ELS board.
The footprint should be good for both. It's a 48-pin quad flatpack.
OK - here we go really carefully. I definitely don't want you to get inadvertently misled. By all means, use the SnapEDA symbol if it fully works for you. I do not get involved with SnapEDA, so I don't know what the imported symbol is like. I wanted mine to have the data stuff connections to the right, and the analogue signal inputs on the left. I suppose one could just edit the import graphic.
The symbol I have posted is not yet perfect in the all the names assigned to the pins, but nearly so, except possibly for Pin 7. That one is called IMPULSE in AD7667, and /NORMAL in AD7622
It takes a step-by-step check to discover exceptions, and this is what I am doing now. Definitely, in the recommended connections diagram, all the electrical functions that matter are on the correct pins.
Checking..
The ones that I see that have any differences, whether in names, or where they are connected in the Figure26, are highlighted in red.
For you, pins 5, 8, 6 connect high, to DVDD. For me, they connect low. The names are correct.
For you, using BYTESWAP, you use pin 4, and IMPULSE pin 7. That is a bit special.
They are shown connected hard to the 0V, meaning DGND.
The BYTESWAP state normally sets up which which data pins the LSB and MSB 8 bits are output to, but can be used to swap the bytes to allow an 8-bit (Teensy) interface. My only comment here is BYTESWAP, delivered from the Teensy, should be delivered relative to OGND on Pin17.
As before, we do not allow Teensy digital returns to find a way to AGND via the DGND on pins 20, 30
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Re: the footprints. Looking at the data sheet, I believe they are identical. Every pin number on the 40-pin flatpack does the same thing. Only one pin I can see has a name that is changed.
I have been stepping through the AD7667 data sheet pin definitions.
Pins 3, and 40 are "NC" not connected on the chip. I have a pin 40 on the symbol named "NC". I managed not to have a pin 3. The footprint will have a pin to solder to, but it has no function.
Other than renaming Pin7 to be IMPULSE, I have not seen any more differences (yet).
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About "HOLE"
When it comes to mounting holes, I once created a component called "HOLE".
Getting more imaginative, I called it "M3_HOLE".
It was basically a huge via, near 7mm full diameter, 3.05mm hole, with no silkscreen on it, so it would "ground" via the mounting screw, like a PC motherboard. Since then, I learned better. That is a great way to share unwanted currents with every other PCB in the chassis!
I still would use the big via, but not connect to the ground plane unless I had good cause.
