[Tinkerphones] Status GTA04A5 and miscellaneous

H. Nikolaus Schaller hns at goldelico.com
Tue Jul 26 11:20:12 CEST 2016

there isn't much to report at the moment about the GTA04A5.

We are still waiting for all components to arrive and the PCBs
to be produced. Let's hope that no news is good news and
cross fingers that it happens soon.

On the software side we have published letux kernel 4.7.0:


It fixes the hdq driver so that we can again read the fuel gauge and
battery state of charge. This is essential to be able to measure
suspend current.

Unfortunately we are still struggling with the charging system.

The symptoms are quite puzzling. On some devices charging
seems to work. While on others it simply fails, does not recognize
cable insertion/unplugging and the ethernet gadget fails as well.

But installing our letux 4.3 kernel on the same SD card and rebooting
makes it work.

What the real mystery is: there is no significant code difference in
the charger driver between 4.3 and 4.4-rc (where it fails for the
first time). So the difference lies somewhere outside the charger
driver but we have not yet found where.

What else can I report?

There was some discussion about a magnetic usb socket for the
GTA04 so that you can no longer pull the GTA04 from the table
through the USB cable and break the USB socket inside the GTA04.

For Micro-USB you can go shopping and find solutions, but not
for Mini-USB.

Therefore I have started to build a prototype for such a thing and
let's hope it works. Then we can build a handful of them (they also
work on GTA01/GTA02 and most Mini-USB devices). It consists
of two PCBs, one with a Mini-USB-Plug and pogo pins and the
other with contact pads and a Mini-USB-Socket. Both will be plugged
together with small magnets glued to the PCB.

As a bonus I have also designed such an adaptor for USB3. Let's
see if that works as well...

And another thing is in works: a tiny AM3358 based breakout
board which has the potential to become the core of a new low-end
tinkerphone... Or just a simple I/O controller (I2C, SPI, USB) with full
Letux inside.

So much for today.


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