[Cryptech Tech] STM32F4 <-> Novena Bridge

[Fredrik Thulin]

On Thursday, June 11, 2015 12:13:51 AM Fredrik Thulin wrote:
> On Friday, June 05, 2015 10:40:29 PM Павел Шатов wrote:
> > Hello!
> > 
> > Fredrik, this is mostly for you. My suggestions regarding connection of
> > STM32F4 to Novena are listed in the attached PDF file.
> 
> I've started this task, see the attached picture for tentative board size
> (10x5 cm) and placements.

Finished routing of the FMC signals. New picture attached.

I tried to be smart about what bunch of traces went to which part of the 
connector, but it was only so much I could do with only two signaling layers.

I ran a length matching report (full output attached) that shows the FMC 
traces are between 29 and 62 mm. I can probably add meanders to increase the 
length of the shortest traces to make everything perhaps 45-62 mm (only 7 
traces shorter than 45), but you (Pavel) helped me do some back-of-the-
envelope calculations in Stockholm that said the traces should not differ by 
more than 150 mm (!) for IIRC 100 MHz signals so maybe it's not worth any more 
effort at all?

For those who haven't studied Bunnies schematics, it say the signals between 
the FPGA and connector are length matched to within 500 mil (1/2 an inch) so 
we're already well within 150 mm.

/Fredrik
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EAGLE Version 7.3.0 Copyright (c) 1988-2015 CadSoft
List of signals with lengthSignal	l [mm]	diff. [mm]	diff. [%]	unrouted [mm]
FMC_NWE	29.554926776	0.000000000	0.000	--
FMC_NOE	33.376306818	3.821380043	12.930	--
FMC_CLK	37.629981795	8.075055020	27.322	--
FMC_A21	37.979360548	8.424433772	28.504	--
FMC_NE1	40.869409643	11.314482867	38.283	--
FMC_D3	41.964201550	12.409274774	41.987	--
FMC_NWAIT	43.528171258	13.973244483	47.279	--
FMC_A20	45.108964469	15.554037694	52.628	--
FMC_A18	45.233500185	15.678573410	53.049	--
FMC_NL	45.749825460	16.194898685	54.796	--
FMC_D12	45.769284313	16.214357538	54.862	--
FMC_D2	45.901465871	16.346539096	55.309	--
FMC_D10	46.046476029	16.491549254	55.800	--
FMC_D11	46.049789738	16.494862962	55.811	--
FMC_D7	46.082512609	16.527585834	55.922	--
FMC_D6	46.220114355	16.665187579	56.387	--
FMC_D9	46.260790126	16.705863351	56.525	--
FMC_D19	46.367304194	16.812377418	56.885	--
FMC_D20	46.370617902	16.815691127	56.896	--
FMC_D8	46.383728712	16.828801936	56.941	--
FMC_D28	46.440279948	16.885353172	57.132	--
FMC_A6	46.522705875	16.967779100	57.411	--
FMC_D18	46.542538192	16.987611416	57.478	--
FMC_A22	46.546364762	16.991437986	57.491	--
FMC_D5	46.578470268	17.023543492	57.600	--
FMC_A17	46.725357213	17.170430437	58.097	--
FMC_A11	46.778949632	17.224022857	58.278	--
FMC_A7	46.983322604	17.428395828	58.970	--
FMC_A8	46.986636312	17.431709537	58.981	--
FMC_A9	46.989950021	17.435023245	58.992	--
FMC_D4	47.006208853	17.451282078	59.047	--
FMC_A10	47.080435924	17.525509148	59.298	--
FMC_D17	47.807654715	18.252727939	61.759	--
FMC_D16	47.881942967	18.327016192	62.010	--
FMC_A16	48.274332390	18.719405615	63.338	--
FMC_D15	49.821998707	20.267071932	68.574	--
FMC_A12	50.017332791	20.462406016	69.235	--
FMC_D29	50.136650337	20.581723562	69.639	--
FMC_D21	50.796854418	21.241927642	71.873	--
FMC_D27	51.058034586	21.503107811	72.756	--
FMC_D26	51.291573236	21.736646461	73.547	--
FMC_D14	51.361761721	21.806834945	73.784	--
FMC_D23	52.481634262	22.926707487	77.573	--
FMC_A13	52.529008892	22.974082117	77.734	--
FMC_A5	52.920825227	23.365898452	79.059	--
FMC_D13	53.049084228	23.494157453	79.493	--
FMC_D22	53.168504852	23.613578077	79.897	--
FMC_D1	53.303650035	23.748723259	80.355	--
FMC_A19	53.437956311	23.883029536	80.809	--
FMC_A14	53.566347478	24.011420702	81.243	--
FMC_D25	53.674093926	24.119167151	81.608	--
FMC_A15	55.139329182	25.584402406	86.566	--
FMC_D31	55.305169975	25.750243200	87.127	--
FMC_D24	55.421729729	25.866802953	87.521	--
FMC_D0	55.910346905	26.355420130	89.174	--
FMC_D30	56.683763048	27.128836272	91.791	--
FMC_A4	56.691947967	27.137021192	91.819	--
FMC_A1	56.734898662	27.179971887	91.964	--
FMC_A3	60.420191140	30.865264365	104.434	--
FMC_A2	61.478571775	31.923644999	108.015	--
FMC_A0	61.871798516	32.316871741	109.345	--