I'm from Austria
And I also ordered now some transmitters and oscillators from mouser and some WM8804 from China (20 pieces each).
My plan is to make also 20 PCBs - so if someone needs PCB/Parts just contact me.
The original HifiBerry boards have it.
I also think that it's just a protection (for example in case there is no HifiBerry software loaded and the portpin is configured as output).
The tinyToslink boards from Jörg don't have it so I guess it's also working without them.
I don't really know what these resistors are for.
Some HifiBerry boards have it (newer ones) and some doesn't.
I didn't found a picture from HifiBerry which is good enough to show the values.
Maybe it's just to check the hardware version of the board and set up the driver correct?
This needs to be tried out when the board is completed.
At least it's in the layout to be on the safe side - the value can be changed easily.
My oscillator has 15pF in the datasheet (I have a very small one).
But it shouldn't make a difference.
Some boards have it, but the HifiBerry Digi boards don't have it, so I guess it's not neccessary.
If the supply should be better I would even prefer to add a extra 3.3V regulator instead of a supply filter (some old HifiBerry boards have this).
The EEPROM is for future features (not implemented yet, but the newest HifiBerry boards already have it on it).
The plan is that the Raspberry Pi detects which board is plugged in with the EEPROM and loads the corresponding drivers/applications automatically.
Basically like USB.
I just put it in the layout to be on the safe side - I will not assemble it for now.
I attached also my first version of the layout.
I kept some connectors free in the middle to be able to connect also other things here (I need to connect my Ambilight here
So I will cut the 20 pin header and solder 2 smaller headers on it.
I tried to keep it quite small.
Maybe I can add the 200Ohm resistors and make it a little bit smaller when I put some resistors on the bottom side - I'll try.