FCDEV3B component quality issues

Das Signal das.signal at freecalypso.org
Wed May 3 08:12:59 UTC 2017


On Tue, May 02, 2017 at 01:13:58PM -0800, Mychaela Falconia wrote:

> In the case of component quality issues, the one component which is
> most suspect is the flash+pSRAM chip Spansion S71PL129NC0HFW4B.
> Openmoko's modem design which we've copied for our FCDEV3B supports
> the option of using several different flash+RAM chips on the same PCB
> footprint, Om's mass-produced units used Samsung K5A3281 (4 MiB of
> flash, 1 MiB of SRAM), but I wanted to use the same high-capacity chip
> found in the Pirelli DP-L10 (16 MiB of flash, 8 MiB of pSRAM), and it
> fits the PCB footprint.  (Another issue with the K5A3281 - Openmoko's
> choice - is that I wasn't able to find a datasheet for this exact part,
> only for some of its relatives, and I am not too comfortable with using
> parts sans proper documentation.)

On this topic I would say the DP-L10 is such a great phone to develop on
and I totally understand why you'd want to reproduce most of its feature.
It has a full Calypso chipset (512 KB of SRAM instead of 256 KB), is
basically unbrickable due to ROM loading, and has a nice screen. There
is also the integrated CP2102 that is really excellent. It's such a
shame this phone is super hard to find. Nonetheless I did manage to find
one on eBay, it was originally a spanish version. It's possible some do
pop up every now and then, try searching for "TC-300". For instance look at
http://www.ebay.es/itm/-/361953505436

Last year I also acquired a bunch of "Peek mobile email" phones; the
original with LoCosto, not the Peek Pronto or Peek 9 (both of which
could have a different SoC). To my surprise the bootloader was not
locked, and by connecting a FTDI to the D+ and D- USB lines I was
able to talk to the ROM bootloader and do a full dump of the phones
using TI's tool that Mychaela found a while back. It's a rather nice
device with a physical keyboard and large screen, even though it
has a LoCosto instead of Calypso. Like the TC-300, a few Peek trickle
on eBay, consider: http://www.ebay.com/itm/-/182489977455

Finally I did a few experiments with a Nokia 3310 (NHM-5) using a very
old tool called knok-phoenix. It appears this phone is also unbrickable,
the flash can be fully erased and after a cold boot one can reupload code
into RAM and run commands. There was a reimplementation of knok on Linux,
which is however buggy; I'm thinking of fixing it just for nostalgia's sake.
The firmware was partially reverse engineered by a team called MADos/project
blacksphere but stopped in 2005.

--DS


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