FCDEV3B V2 boards are here

Mychaela Falconia mychaela.falconia at gmail.com
Sat Jan 12 21:59:53 UTC 2019

Hello FreeCalypso community,

I am overjoyed to announce that our FCDEV3B V2 boards are finally here:
last night I have tested the first batch of 8 boards which I picked up
from Technotronix on Thursday.  Here are the findings:

Yield: out of the total of 8 boards in this batch, 5 are good and 3
have defects.  Out of the 3 defective boards, one has perfectly working
RF but is unable to talk to the SIM in the socket, while the other two
have RF defects: one has totally dead RF (both Rx and Tx, all 3 bands),
the other exhibits a bad Rx path for the low band, but the rest works.
In the case of the board on which only the SIM interface doesn't work,
we have previously encountered the same symptoms in one of our earlier
FCDEV3B V1 batches, and replacing the SIM socket made it work, hence I
am going to try the same on this board.  In the case of the two boards
with different RF defects, I will have a discussion with Technotronix
about failure analysis.  But even if we are not able to fix any of
those 3 defective boards, we still have 5 perfectly good ones from
this batch.

V2 changes: unlike our previous FCDEV3B V1 boards, these new V2 boards
have perfectly working sleep while keeping our high-capacity Spansion
S71PL129NC0HFW4B flash+pSRAM chip!  Thus we now have proof that my
innovative (not from TI, not from OM, not from Pirelli) flash reset
circuit change is working as I intended.  With my recent changes to
the firmware we have regained flash chip type autodetection, thus we
can now populate either this big Spansion flash+pSRAM chip or the
smaller Samsung flash+RAM chip that was used by Openmoko and have the
same fw build work with both, but for our development boards we are
keeping the big version for the obvious reason: large flash and RAM
capacity is very handy for development.  If anyone ever pays for the
development of a commercial FreeCalypso modem module in a small SMT
form factor, that version can use the smaller memory capacity more
appropriate for a production modem.

Out of the 5 defect-free boards in this batch, the availability is as
follows: one board I need to keep for myself, one more board is
earmarked for Rafael (Rhizomatica), and the other 3 are now available
for commercial users at the regular price of $500 USD each.  If the
latter 3 boards are not bought quickly by the people I have in mind,
at least one of them will be reallocated to FreeCalypso marketing
outreach purposes: I would like to offer a free board to anyone from
the ofono developer community who would be willing to get our FC modem
product family properly supported in ofono.  Aside from the 3 defective
boards which may or may not be repairable, I still have 3 unpopulated
PCB panels, enough for 12 more boards before needing another PCB fab
run - but I will need to do a thorough round of failure analysis with
Technotronix before we assemble that next batch.

The next steps for me are:

* I need to add the new sleep mode configuration I mentioned before,
the one that enables big and small sleep, but not deep sleep, for
those users who would rather not be burdened with making their host
interface software sleep-aware, and who are willing to live with
greater power draw in return for interface simplicity - engineering is
all about trade-offs and compromises.

* I need to test one of those 8 ohm 0.5 W speakers I bought from
SparkFun and see if they perform as well as the similar-looking
unknown-origin speaker that was donated to me by a member of my local
LUG.  If these SparkFun speakers work well, I'll be able to recommend
them as an official choice for FCDEV3B lab bench setups, otherwise I
will have to go back on the hunt for a suitable speaker.

* I will need to write a sleep-aware userspace implementation of the
GSM 07.10 MUX (which our FC modem supports) to serve as an exerciser
for this feature of our modems, and add it to our FC host tools suite.

* Once all of the above are done, I will need to make an updated
version of the user's manual for the FCDEV3B, and only then the
current iteration of our modem product development will be considered

* After all of the above, I will need to get back to the project of
bringing up my BeagleBoard-xM and interfacing it to our FCDEV3B, for
the purpose of exercising digital voice over MCSI and making it work.
If anyone else has a need for this digital voice interface and has
something else (othen than BB-xM) to connect to it for testing, feel
free to beat me to it!

Hasta la Victoria, Siempre,
Mychaela aka The Mother

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