On Monday, May 31, 2021 at 5:14:09 PM UTC-7, jla...@highlandsniptechnology.com wrote:
> On Mon, 31 May 2021 13:45:44 -0700 (PDT), Ed Lee
> <edward....@gmail.com> wrote:
>
> >On Monday, May 31, 2021 at 1:40:27 PM UTC-7, John Larkin wrote:
> >> On Mon, 31 May 2021 13:37:05 -0700 (PDT), Ed Lee
> >> <edward....@gmail.com> wrote:
> >>
> >> >On Monday, May 31, 2021 at 1:26:03 PM UTC-7, John Larkin wrote:
> >> >> On Mon, 31 May 2021 21:07:24 +0200, Johann Klammer
> >> >> <klam...@NOSPAM.a1.net> wrote:
> >> >>
> >> >> >On 05/31/2021 02:59 AM, jla...@highlandsniptechnology.com wrote:
> >> >> >>
> >> >> >> https://www.digikey.com/en/resources/dkred
> >> >> >>
> >> >> >> Anybody tried them?
> >> >> >>
> >> >> >>
> >> >> >>
> >> >> >Hmmm..
> >> >> >
> >> >> >Copper Layers 2
> >> >> Better than one!
> >> >>
> >> >> I wonder if they have a 4-layer option.
> >> >
> >> >Yes somewhere (i remember a 4 layers quick proto, but cost much more than 2x 2 layers) , I would prototype 2 pcs of 2 layers, but make 4 layers in production.
> >> How do you do that? Stack boards with a jillion little wires to
> >> connect all the vias?
> >
> >Yes, line up all the holes and vias. Just a straight wires between boards. It's ugly, but reliable enough for proto.
> And labor intensive.
> >
> >>
> >> 4-layer protos are cheap nowadays. Just make sure they will follow
> >> your stackup.
> >
> >It's also easier to debug mult-board stackup. You can't see the traces inside 4 layers proto.
> Do you need to? Besides, once you solder all those vias the inner
e> traces are inaccessable and invisible.

The top and middle boards are soldered together, via the wings. The combined board plugs into a ZIP40 socket, no soldering.

> My 4-layer boards are usually traces, ground, power pours, traces. The
> inner layers aren't very interesting.

Mines are all traces. I don't have ground planes.

The black pill (STM32F411, QFN48) has around 20 usable ports on a DIP40. I have around 10 common pins so far. It might be too difficult to make it totally pin compatible without using too many vias, or too big the board.

I am trying to fit a TQFP100 on a DIP40. The chip overlaps the middle pins, so i don't have pins there.

COTS board is easy to get started, but just as easy to run into limitations.

Ed Lee wrote:
> On Monday, May 31, 2021 at 1:26:03 PM UTC-7, John Larkin wrote:
>> On Mon, 31 May 2021 21:07:24 +0200, Johann Klammer
>> <klam...@NOSPAM.a1.net> wrote:
>>
>>> On 05/31/2021 02:59 AM, jla...@highlandsniptechnology.com wrote:
>>>>
>>>> https://www.digikey.com/en/resources/dkred
>>>>
>>>> Anybody tried them?
>>>>
>>>>
>>>>
>>> Hmmm..
>>>
>>> Copper Layers 2
>> Better than one!
>>
>> I wonder if they have a 4-layer option.
>
> Yes somewhere (i remember a 4 layers quick proto, but cost much more
> than 2x 2 layers) , I would prototype 2 pcs of 2 layers, but make 4
> layers in production.
>

The stackup change makes the strays hideously different though.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

On Tuesday, June 1, 2021 at 6:43:09 AM UTC-7, Phil Hobbs wrote:
> Ed Lee wrote:
> > On Monday, May 31, 2021 at 1:26:03 PM UTC-7, John Larkin wrote:
> >> On Mon, 31 May 2021 21:07:24 +0200, Johann Klammer
> >> <klam...@NOSPAM.a1.net> wrote:
> >>
> >>> On 05/31/2021 02:59 AM, jla...@highlandsniptechnology.com wrote:
> >>>>
> >>>> https://www.digikey.com/en/resources/dkred
> >>>>
> >>>> Anybody tried them?
> >>>>
> >>>>
> >>>>
> >>> Hmmm..
> >>>
> >>> Copper Layers 2
> >> Better than one!
> >>
> >> I wonder if they have a 4-layer option.
> >
> > Yes somewhere (i remember a 4 layers quick proto, but cost much more
> > than 2x 2 layers) , I would prototype 2 pcs of 2 layers, but make 4
> > layers in production.
> >
> The stackup change makes the strays hideously different though.

Yes, give up making it compatible.
I will have to go with a 4 boards solution.

1. Shuttle board on XL & XR (eXtreme Left and Right).
2. WingDip STM32F469/411 in QFP100.
3. Shape shifter to bring middle 6 pins of LW and RW
(Left and Right Wing) back to the center.
4. Base board with 40 pins ZIF.

The $20 469 (1M flash) is easier to order than the $10 411.

______XL___LW___L_____R____RW___XR____|_______B/B____
_1_____________VB___3v3_______________|____B12____5v
_2____________-*-___Gnd_______________|____B13___Gnd
_3____________-*-____5v_______________|____B14___3v3
_4____________-*-____B9_______________|____B15___B10
_5____VB__-*-_-*-____B8___-*-__3v3____|_____A8____B2
_6___-*-__-*-_-*-____B7___-*-__-*-____|_____A9____B1
_7___-*-__-*-__A1____A6___-*-__-*-____|____A10____B0
_8___-*-___E3______________B5__-*-____|____A11____A7
_9____E4__C13_____________A10__-*-____|____A12____A6
10___C14___OI______________C7___A9____|____A15____A5
11____OO___C2_____________D12___C6____|_____B3____A4
12____C3___VA_____________B15__D11____|_____B4____A3
13____A0__-*-_____________-*-__B14____|_____B5____A3
14___-*-__-*-__A3____A2___-*-__-*-____|_____B6____A1
15___-*-__GND__A6___B11___-*-__-*-____|_____B5____A0
16____5v___C4__B1___E15___-*-__Gnd____|_____B8_____R
17____________-*-___-*-_______________|_____B9___C15
18_____________5v___-*-_______________|_____5v___C14
19____________Gnd___-*-_______________|____Gnd___C13
20____________3v3_____________________|____3v3____VB