[Gta04-owner] Antwort: Re: GTA04A5 - IrDA

Sven Dyroff S.Dyroff at phytec.de
Tue Jan 8 11:45:23 CET 2013


first an happy new year to all!

I still intend to use IrDA instead of UART in order to have an wireless 
debug connection. On the host side, this seems to be a very easy task, 
thanks to chips like these:

For example from Digikey you can get an IR-adapter like the TFDU4100:

You can easily wire it with the encoder/decoder-chip and connect it to 
something like this:

Then you even don't need any UART on the host anymore in order to debug. I 
even think that GD could provide this easily as an optional cable like the 

Unfortunately it has turned out, that on the target side things are quite 
complicated. It's not enough just to switch some bits within the OMAP3 in 
order to get a simple serial connection over IrDA. Instead of this, you 
need a complete driver that is able to run a higher protocol.

Some searching in the net reveals a very nicely source named "omap-ir.c". 
But as you can see, it's a networking driver for Linux, based on socket 
communication. What we need is a concole driver for MLO and bootloader. My 
first trial to rewrite the driver got stuck very soon, because I'm not an 
expert for that. In the attachment you'll find my feeble result. Perhaps 
its at least useful for inspiring someone other on this list...

Best regards

Von:    NeilBrown <neilb at suse.de>
An:     "Dr. H. Nikolaus Schaller" <hns at goldelico.com>
Kopie:  List for communicating with real GTA04 owners 
<gta04-owner at goldelico.com>
Datum:  07.01.2013 23:10
Betreff:        Re: [Gta04-owner] GTA04A5 - was 8mW sleep for Beagle Board
Gesendet von:   gta04-owner-bounces at goldelico.com

On Mon, 7 Jan 2013 18:55:52 +0100 "Dr. H. Nikolaus Schaller"
<hns at goldelico.com> wrote:

> Am 07.01.2013 um 04:56 schrieb NeilBrown:
> > On Fri, 4 Jan 2013 11:51:38 +0100 "Dr. H. Nikolaus Schaller"
> > <hns at goldelico.com> wrote:
> >
> >>
> >> Am 04.01.2013 um 10:21 schrieb Radek Polak:
> >>
> >>> On Thursday, January 03, 2013 01:09:53 AM NeilBrown wrote:
> >>>
> >>>> On Tue, 1 Jan 2013 16:29:45 +0100 Radek Polak <psonek2 at seznam.cz> 
> >>>>> Hi,
> >>>>> i found this mail:
> >>>>>
> >>>>> 
> >>>>> Cg
> >>>>>
> >>>>> Do i count right? 8mW means 2mA on 4V battery. I wonder if we 
could apply
> >>>>> this also on GTA04.
> >>>>
> >>>> The first patch is a useful guide for writing similar code for the 
> >>>> The remainder aren't particularly relevant I think - the relevant
> >>>> functionality is already in mainline.
> >>>
> >>> I wonder about the HW changes - if they can be also applied on 
> >>
> >> It is on the GTA04A5 todo list. At least the "disable 26MHz 
oscillator" patch.
> >>
> >
> > What else is on the A5 todo list?  I'm particularly hoping that 
inserting the
> > headset plug will cause an interrupt.
> > Any chance of seeing the schematics before you commit to them :-?
> Yes, that is planned to be finalized this week.
> Important (i.e. kernel relevant) changes are so far:
> * power down 26 MHz oscillator through switching off VPLL1 (tbc.)
> * LIS302 option removed completely
> * LSM303 option removed completely
> * BMA180 / HMC5883 replaced by BMC050
> * GPS-chip has 1 second pulse - connected to GPIO114 (was connected to 
> * IrDA can be separately enabled/disabled (GPIO175 or TGPIO7 - tbc.)
> * TCA8418 replaced by FFC connector (for external keyboard)
> * there will be an optional connection that a 3G wakeup can simulate 
pressing the power key (tbc.)
> * switch in headset jack will pull down a GPIO if no headset is inserted 
> * RESET-OUT from UMTS module connected to a GPIO so that it is possible 
to detect if it is really running (tbc.)

Sounds good. thanks.

Though I wonder a bit about IrDA - does anyone actually care about that? I
would imagine that most situations that would once have used IrDA would 
be using bluetooth.
The OMAP3 is capable of generating CIR (Consumer IR) signals which most
consumer electronics remote controls use.  That might be more useful, 
it needs to be wired differently.
The CIR signal goes out on the uart3_cts_rctx  pin, where as IrDA goes out 
uart3_tx_irtx - So I don't think they can use the same IrLED (???).

> Some options are a little critical and can't be tested before building 
the first devices.
> So there will be hardware options to disable/remove them if they don't 
work well enough.
> Non-software related changes replace some obsolete components, improve 
> GPS antenna switch, reduce noise generated by SD card interface, and 
make a
> really complete case kit possible with components from continued 
> But at the moment it does not look as if there is any demand for a 
GTA04A5 board.
> So far there is exactly 1 preorder for a GTA04A5 board...

That's a shame.  Maybe demand will pick up as Christmas gets further and
further into the past...

[Anhang "signature.asc" gelöscht von Sven Dyroff/Mainz/Phytec] 
Gta04-owner mailing list
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