Stuffing Serial Bluetooth Module Inside C1k Casing

[utx]

So have you tried running it off of just the Z's USB power? I may be interested in getting one if it worked without an external hub.

Yes, does not work. Vanilla 2.6.23 rejects to power it. After patching, 5V voltage sends pulses, as Zaurus regularly starts it and stops due to overcurrent. (note that albert provided a simple hwmod to get >500mA form Z).

I tried to connect 5V from the Z power adapter directly to the dongle 5V pins. Then it started to work. (It's usable only for testing - it probably initiates short circuit protection inside Z.)

I plan to desolder the voltage regulator and try to connect 3.3V directly from the IOPORT connector. (But for such things I have to buy my own dongle.)

[cycle_55]

So have you tried running it off of just the Z's USB power? I may be interested in getting one if it worked without an external hub.

Yes, does not work. Vanilla 2.6.23 rejects to power it. After patching, 5V voltage sends pulses, as Zaurus regularly starts it and stops due to overcurrent. (note that albert provided a simple hwmod to get >500mA form Z).

I tried to connect 5V from the Z power adapter directly to the dongle 5V pins. Then it started to work. (It's usable only for testing - it probably initiates short circuit protection inside Z.)

I plan to desolder the voltage regulator and try to connect 3.3V directly from the IOPORT connector. (But for such things I have to buy my own dongle.)

This is slightly off the present topic but would it be possible to add a couple of usb ports in the cf slot? If it is, then it would be possible to use the princeton PTM-UBT3S adapter which works in the Z without external power. One would, of course, lose the cf slot in the 3x00. On a 1000 it could be used internally where the HD would sit. I would like to do this on my 3100, what do you think. Thanks.

cycle_55

[utx]

This is slightly off the present topic but would it be possible to add a couple of usb ports in the cf slot? If it is, then it would be possible to use the princeton PTM-UBT3S adapter which works in the Z without external power. One would, of course, lose the cf slot in the 3x00. On a 1000 it could be used internally where the HD would sit. I would like to do this on my 3100, what do you think. Thanks.

Probably all Bluetooth adapters work in Z without external power and probably no WLAN card can live with 150mA (actually, kernel gives 150mA, but overvoltage protection stops the current at about 180mA).

It may be easy to hack BT dongle and replace USB-A connector with USB-mini-A connector. But Princeton PTM-UBT3S may not be a good start point for hacking. It uses a trick to make it so small - the Bluetooth chip is located inside the USB connector in the place, where you can normally find the insulation plate. So it is a bit risky to disassembe it.

There are very few CF->USB cards, and I don't know, whether they work in Linux. It is very specialized and hard to find harware: AFAIK only SolarExpress® PDA II from Twin Paradox is in production. You can also find discontinued CFU1U from Ratoc Systems and discontinued Kernel concepts Systementwicklung Interpocket USB-Host CF Karte. All of them have the extender or special connector with "pigtail" cable.

Much simpler to buy is a CF->Bluetooth card. But AFAIK only one fits completely to the slot - pretty expensive Bluetooth CF Card from Socket Mobile, inc.

The fact, that my WLAN CF card has a large extension part makes me very uncomfortable when I am typing (it can even cause painfull bruise) and forced me to start thinking about another solution of connectivity.

And finally, Zaurus chipset (PXA270) has three USB hosts. One (OTG) is available in the external connector and remaining two are only inside the body.

[cycle_55]

Probably all Bluetooth adapters work in Z without external power and probably no WLAN card can live with 150mA (actually, kernel gives 150mA, but overvoltage protection stops the current at about 180mA).

It may be easy to hack BT dongle and replace USB-A connector with USB-mini-A connector. But Princeton PTM-UBT3S may not be a good start point for hacking. It uses a trick to make it so small - the Bluetooth chip is located inside the USB connector in the place, where you can normally find the insulation plate. So it is a bit risky to disassembe it.

There are very few CF->USB cards, and I don't know, whether they work in Linux. It is very specialized and hard to find harware: AFAIK only SolarExpress® PDA II from Twin Paradox is in production. You can also find discontinued CFU1U from Ratoc Systems and discontinued Kernel concepts Systementwicklung Interpocket USB-Host CF Karte. All of them have the extender or special connector with "pigtail" cable.

Much simpler to buy is a CF->Bluetooth card. But AFAIK only one fits completely to the slot - pretty expensive Bluetooth CF Card from Socket Mobile, inc.

The fact, that my WLAN CF card has a large extension part makes me very uncomfortable when I am typing (it can even cause painfull bruise) and forced me to start thinking about another solution of connectivity.

And finally, Zaurus chipset (PXA270) has three USB hosts. One (OTG) is available in the external connector and remaining two are only inside the body.

What I am thinking of doing is basically  putting a two port usb hub inside the cf slot. The posts would be staggered so that the bluetooth and wifi adapters would just protrude a very minimum amount. Just enough so they can be removed. Just a recurring thought I've been having. Thanks.

cycle_55

[utx]

there still was an issue with power.

And on the web: The only time the gpio 93 would go low was after shutting down the system AND going on battery. I had no time to figure out a solution
Hi there.

Intel® PXA27x Processor Family Design Guide mentions this problem. You have to program GPIO pin sleep behavior to fix it. It could be done in kernel or maybe using an utility called pxaregs. It's easy to fix and compile, but it supports only PXA255 (which does not have GPIO93), so it needs somebody, who will port it to PXA270.

[utx]

If there is somebody still interested:

I guess I was able to identify nearly all open parts on the Akita board that were probably intended to be soldered to get Bluetooth working (see the photo). Note that all parts are are only my guesses, and I have no plans to test it (I don't have Akita). It's just for learning, how it was done by professionals.

I think that nobody want to use exactly these parts, but it may be an inspiration for modders.

Notes to parts:

Mitsumi WML-C19NHN: Board is ready for just this one variant. Modern modules can live without 1.8V power. With WML-C19NBN variant you need to change software, with WML-C19NHR variant you can omit 1.8V regulator, with WML-C19AHN you may omit antenna elements (however you would probably get a bit worse signal deeper in the case). There are more modern modules pin-compatible with this one, from both Mitsumi and thirs parties.

Seiko S-T111B33MC and S-T111B18MC: Board is ready for T111B variant of low drop linear regulators.

TDK CABPB0730A: A ceramic patch antenna. CABPB0715A would fit as well.

Double T-member between module and antenna: However antenna data sheets talk about customization of parts there, most hardware vendors stay at 0R in signal path and with open positions in grounding elements (or 3.9pF in the position nearest to the module).

unidentified part: It seems that module had problems with reset. The part may be a diode or Zener diode lowering voltage during non-reset conditions.

Considerations:

For low power 3.3V devices it's better to convert the voltage from AC/battery to 3.3V (or even low power 1.8V) with a low drop linear regulator. Linear regulator efficiency is about 3.3V/battery_voltage (and efficiency while running on AC is less critical), switching step-down may have about 80% at 3.3V and 60mA.

If I did not oversee something, Sharp did not use any RF-kill switch (extra GPIO). (It needs to be checked. If it is true Vin pin of regulators is wired directly with with the main AC/battery power.

There may be problems with reset. Note that moderm modules don't need reset to start properly. But you may still need reset after sending a bad command. Battery removal is not comfortable.

[speculatrix]

If there is somebody still interested:

I guess I was able to identify nearly all open parts on the Akita board

...snip...

Hi UTX,
thanks very much for that useful posting. Yes, I am still interested, and so are others. In fact, as our Zauruses get older and less valuable, many of us might be more willing to take out the soldering iron and consider having a hack at them  

cheers
Paul

[utx]

In fact, as our Zauruses get older and less valuable, many of us might be more willing to take out the soldering iron and consider having a hack at them

Well, before trying to hack your Akita with the above:

- Verify, that Vin pins of regulators are really connected to VAC/Batt (un-stabilized voltage from battery or AC adapter (what gives more)).

- Verify, that reset is really wired (optional).

- The module is really ancient and probably out of production. Use of a modern pin compatible Bluetooth 2.1+EDR module shoud be possible. Newer modules don't need 1.8V and can work with auto reset. Not only Mitsumi produces pin compatible modules. At least Roving Networks do them as well.

- Depending on module version, you may consult the datasheet and check method of switching between modes and protocols (on the old Mitsumi it was provided probably by the two resistor to AIO pins). You need to activate UART modes, either ther H4 or BCSP. Sharp used H4, but if you don't plan to depend on Sharp software, BCSP may be a better option, as it allows deeper sleep modes (thanks to protocol for resending bits lost while sleeping). With BCSP you can also optionally repurpose two of four GPIO pins.

- Regulators mentioned above are not available in small quantities. You have to find any similar pin compatible IC. It must be a low-drop regulator. Cheap regulator need input 3V higher than input. Low drop regulators can work with 0.05V difference.

- Mentioned antenna is probably hard to get as well.

And this is valid in general:

- Buy only modules with HCI firmware. Modules with SPP firmware are ofter cheaper, but useful only as a wireless serial port. Without signing a NDA with CSR, you have only small chance to change the firmware. For the same reason, prefer cheaper ROM version of modules, because you will probably not be able to change firmware anyway.

- Consult datasheets and verify, that my guesses are correct!

- While ordering a part, check also letters after the IC number. They may mean incompatible variant or different firmware.

I have Terrier and this space is occupied by HDD, so I will not try it for sure, but I am trying to learn and finally design a small daughter board. (Now I am learning to work with gEDA.)