On 04/05/12 01:23, Peter Stuge wrote:
Oliver Schinagl wrote:
Unfortunately I have had little feedback so far.
But here's a small
Thanks for the update.
I did look at your previous board but needed more time to really look
That would be grand!
I have finally received my SO8 memory modules and
those babies are
Oh it's not so bad. :) Try the 0603 resistors.
Because of this, I have replaced the SO8M
footprint with an SO8W
This is actually correct. All SPI flash chips used in PCs are in the
200 mil wide package, not the standard SO8 which is only 150 mil.
There are 3 SO8 package footprints in PCB, SO8, SO8M and SO8W. None fit
'perfectly'. S08 is way to small to be usefull, SO8M fits 'perfectly'
but makes it extremly hard to solder I recon, since the pad, ends at the
legs. SO8W seems to be a little to wide, the legs end up perfectly on
the inner sides, which might make it not to cover the back 'cavities'
perfectly? But I guess it will have to do.
The PCB's that I used as inspiration actually do fit perfectly :)
I've also saw a screenshot of an Asus
motherboard that had the bios chip
right next to a Sata port, in the wrong/different orientation, so I've
added a 3rd design so all 3 possible insertations are possible. (Left,
center and right facing connector).
Ah, so the plan is that your PCB is plugged into the factory BIOS
socket? That's a nice idea, but as you discovered there are four ways
that the chip can be oriented, so you really have to make four
boards to have a solution that works on every board. :\
Yes, the plan was to have
the PCB go into the motherboard, and the
original bios piggy bags ontop! The
Well, 4 orientations, but I think 1 can be used for 2 orientations. It
all depends on what is blocking your board however.
I hope it's quite unlikly that a bios is constrained on 3 sides, but as
always possible. If I get bored later this week, I may end up making the
missing 4th design then, where the socket sits 'sideways'. Should be
considerably easier to route then the ones I have now ...
I've attached the gEDA .pcb file with the 3
Thanks. I'll try to give some more detailed feedback, but one big
no-no that I've seen already is that your silk is covering pads.
Noone will do any cropping for you, so you will indeed get silkscreen
on your pads, which 1) potentially makes the board house unhappy
because it may make a mess in their machines, and 2) makes it
difficult for solder to flow over the pad.
Hmm, I assumed silk screening is applied
last, as I have seen
soldermasks and silkscreening covering via's. The only thing I cover IS
via's ... because of that assumption.
When sending out the final rev. I'll
copy/paste the silk screens
from the left design so they all look identical.
No, please do not make design changes post final review. Another way
to express this is please only send files for review that you believe
that you are finished with. Of course there can be iterations and
that's fine! But don't make further changes after the final
I should have clarified this yes, I would of course have posted the
final version that would have been sent off to the board house. But that
version will fail DRC checking :(