[Gta04-owner] GTA04A5: you will hate and you will love this mail

Thu Feb 11 22:04:48 CET 2016

Thanks Nikolaus very much for the update.

Re: the WL1835 vs. WL1837, I agree with the other posters that the addition
of 5GHz wifi is worth the additional ~20EUR.  I looked briefly at an
overview [0], and it looks like the WL1837 is also spec-ed for "industrial"
temperatures (-40C to 85C), whereas the WL1835 is spec-ed for "commercial"
(-20C to 70C) -- is that correct?  While that's great in itself of course,
I might be concerned that the chip intended for industrial use may not be
as power-efficient?

Cheers,
- Chris

[0] http://processors.wiki.ti.com/index.php/WL18xx_Overview

On Thu, Feb 11, 2016 at 8:37 AM, H. Nikolaus Schaller <hns at goldelico.com>
wrote:

> Hi Neil, hi Thierry,
>
> Am 11.02.2016 um 17:02 schrieb Neil Jerram <neil at ossau.homelinux.net>:
>
> > FYI this is a bit 'tl;dr' for me.  Actually I did read it quite well, but
> > still struggled to see the overall message
>
> ok, sorry for that. It always happens if you collect a lot of information
> but
> don't have enough time to write a well-designed posting.
>
> > - GTA04A5 is still alive but will
> > take longer than planned?
>
> Yes. A longer that planned and last time announced, but not much.
>
> In fact to answer the question of Thierry, there is a good chance that the
> final
> order for production can be done as early as by end of next week. There
> isn't
> much to be done (some paperwork, checking/improving the PCB layout for
> another time, testing the 1GB RAM chip).
>
> How long it takes to get the remaining components is guesswork but
> ~4 weeks until the first PCBs can be built is a good guess.
>
> There are only two open questions:
> * RAM verification which needs us to succeed in replacing a RAM chip in an
> old GTA04
> * WL1835 or WL1837? The latter being ~20 EUR more expensive but having
> 2.4GHZ / 5.8 GHz
>
> What are your opinions on the WL1835/37?
>
> BR,
> Nikolaus
>
> >
> > So, please consider adding a summary.
> >
> > -----Original Message-----
> > From: gta04-owner-bounces at goldelico.com
> > [mailto:gta04-owner-bounces at goldelico.com] On Behalf Of H. Nikolaus
> Schaller
> > Sent: 10 February 2016 19:28
> > To: List for communicating with real GTA04 owners
> > <gta04-owner at goldelico.com>
> > Subject: [Gta04-owner] GTA04A5: you will hate and you will love this mail
> >
> > Hi all,
> > you might wonder what the status of the GTA04A5 is.
> >
> > Unfortunately there has not been much progress since I had to spend much
> > more time on making the Pyra (OMAP5) hardware working and verifying that
> it
> > is indeed mass production ready than anticipated. This was really
> exhausting
> > because it was squeezing a phase that would normally need several months
> > into just some weeks.
> >
> > There had been a lot of details to be fixed. Not much if you see the
> result,
> > but each issue needed 110% attention for several days until a reliable
> fix
> > was found (and some are still open). For example, there were boot
> problems,
> > where the Linux did sometimes start to boot, but suddenly stopped.
> Sometimes
> > it reported CRC errors.
> >
> > This turned out to be a 15pF capacitor to attenuate the MMC clock signal
> > since it may disturb the GPS receiver (63th harmonic of the
> > 25 MHz clock). A lesson we learned twice for the GTA02 and GTA04.
> >
> > But this time the 15pF was good for GPS but too much for the MMC.
> > It made the MMC interface of the OMAP5 to fail spuriously. Such bugs make
> > grey hair and need a lot of time - and can't be parallelised by having
> more
> > people to work on it.
> >
> > But now, we are almost through and the OMAP5 is starting to work
> reliably.
> >
> > This has a nice side-effect, which is very important for the GTA04A5
> project
> > and the reason why I report it today.
> >
> > The GTA04A5 needs some replacement components because the old ones used
> in
> > the GTA04A3 and A4 are no longer available. Even for money.
> >
> > One of them is the WLAN/BT combo W2CBW003.
> >
> > So the plan is to replace it by a modern WL1835 module [1] which adds
> more
> > WLAN frequencies, speed and adds Bluetooth BLE 4.0.
> >
> > But it would be risky to throw it into the schematics, make a PCB layout
> and
> > build the ~100 GTA04A5 we have on plan. The risk is that it does not work
> > and we have no chance and money to fix.
> >
> > Fortunately, the Pyra also has such a module :) And yesterday, I was
> able to
> > get it alive for WLAN and today for Bluetooth. This means that the way
> it is
> > wired up to the OMAP5 MMC4 interface and UART2 is working!
> >
> > And, the way the setup is done in the Device Tree also works.
> >
> > Since the OMAP3 is not different for these interfaces, I am now sure
> that we
> > will not make a mistake if we throw in the WL1835 into the GTA04A5. This
> is
> > the good thing! It simply will work with the 4.5-rc3 kernel (and slightly
> > different commands in user space).
> >
> > The other decision blocking the GTA04A5 production is the 1GB RAM/NAND
> chip.
> > Before deciding to solder them all on the ~100 GTA04A5 boards, I would
> >
> > like to test it a little with some old (partially broken) GTA04 board.
> This
> > means desoldering the original 512 MB PoP (Package on Package) RAM/NAND
> > chip. But without damaging the DM3730 CPU. And then solder the different
> PoP
> > chip on top [2].
> >
> > Desoldering is easy (since we now have a new vapour phase machine with
> BGA
> > desoldering tools). But soldering a new chip, especially Package on
> Package
> > is really tricky. First experiments did make the new chip swim away so
> that
> > it was soldered in a wrong position :(
> >
> > Therefore we have aborted that to find a solution. There are ideas, but
> this
> > needs more experimentation time (i.e. days) until it becomes successful.
> > Unfortunately another topic queued up behind making the Pyra handheld
> > production ready.
> >
> > So I have to apologize that we can't keep the availability date, but it
> is
> > really not much missing. Except time to do what is needed.
> >
> > I am really sorry for that delay which might come a little unexpected
> since
> > I did not even give some status updates in the last weeks.
> > This is something I promise to change again.
> >
> > There is also something on the horizon: a Kernel and QtMoko hacking
> weekend.
> > The plan is to meet in some cosy place and have some core hackers just
> work
> > in two teams to fix remaining kernel issues on one side and overhaul
> QtMoko
> > to run on top of stock Debian Jessie. Replicant will also be represented,
> > and we hope that we can then even use our Letux standard kernel for
> > Replicant.
> >
> > Please let me know if you want to participate/contribute.
> >
> > And of course if you have questions about the GTA04A5.
> >
> > A final note: we have a new mailing list for Letux kernel development
> [3] so
> > that this list does no longer need to be cluttered by tiny details and
> patch
> > discussions.
> >
> > Sorry again for the delay and thanks for your patience.
> >
> > -- Nikolaus
> >
> > [1]: http://www.ti.com/product/WL1835MOD
> > [2]: https://en.wikipedia.org/wiki/Package_on_package
> > just a note: we have the "or less" variant in the picture: 0.5mm on top
> and
> > 0.4mm on bottom
> > [3]: http://lists.openphoenux.org/mailman/listinfo.cgi/letux-kernel
> >
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