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

Christoph Mair christoph.mair at gmail.com
Thu Feb 11 23:25:47 CET 2016


"Industrial" temp-range usually means they used better components which
were tested to work at these temperatures. I've never seen a difference in
power consumption, when measured at equal conditions. Efficiency might
decrease at 80°C compared to 20°C but around room temperatures they should
not differ.

Best regards,
  Christoph
Am 11.02.2016 10:05 nachm. schrieb "Chris Dellin" <cdellin at gmail.com>:

> 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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