Stuffing Serial Bluetooth Module Inside C1k Casing, share your success stories ... Options

[albertr]

Since I haven't yet read/seen any posts about success stories on the subj (except for someone who claimed he added a usb bt dongle, but didn't support it by any tech info/pics), I'm getting ready to perform a first surgery on my C1K. Time permitting, I hope to do it sometime next week (maybe on July 4th holiday weekend).

Here's a few thoughts I have on the subj:
- There's a ffuart wired up to a port on the back of the C1K (so-called sharp i/o port) that has all modem control lines. I'm leaving it as a last resort (if everything else fails), since I want to retain it for rs232 comm.
- There's a btuart in PXA270 that has CTS/RTS control lines, but it's unknown if Sharp traced it on PCB. I would guess that it would make sense to have it traced just in case, i.e. planning for future models with built-in BT, but with Sharp you never know...
- Well, it leaves us with stuart that is wired up to IRDA transmitter/diode, but doesn't have any control lines, so hardware flow control is not possible.

If btuart lines can't be traced, either rs232 or irda has to go. Personally, I don't use IRDA myself, so for me the choice is clear. But not having hardware flow control leaves us with a challange of fighting high interrupt latency of bloated Sharp's kernel to avoid fifo overruns. I took a look at Sharp's serial driver, and as usual with sharp it's ... well, not good. I had troubles with overruns even at modest speeds. Now, the good thing is that it;s Intel PXA270, not Sharp's proprientary hardware, so full tech specs are available. I spend a few hours on "unsharp'ing" the serial driver, so now it seems to run ok. I tested it @ 460800 and not getting overruns anymore. I still need to test it @ 921600 and implement suspend/resume hooks, maybe add some hooks to front LED to show activity, etc.

Anyway, just thought it would be useful to have a dedicated thread where we all can share tech info and success stories. Please feel free to contribute... and I'll update you on status of my surgery.
-albertr

[albertr]

What about stuart? In case you don;t need SIR.
-albertr

[2x4ever]

I believe the scoop is a proprientary Sharp's ASIC, so the datasheet most probably never would be published or made public.

Yes it is an ASIC but by EPSON: http://www.eea.epson.com/go/Prod_Admin/Cat...ays.GA_SLA50000
This is a gate array and we probably will never know what sharp has putted into it. It is a pity.

What about stuart? In case you don;t need SIR.

I'd better use FFUART since it have RTS/CTS lines. And stuart is such slow as ffuart is.

[speculatrix]

Yes it is an ASIC but by EPSON: http://www.eea.epson.com/go/Prod_Admin/Cat...ays.GA_SLA50000
This is a gate array and we probably will never know what sharp has putted into it. It is a pity.

not necessarily.. it depends on how the gate array is programmed. if it's programmed by Epson, then we're out of luck. If it's a field programmable array and programmed on the board, then maybe just maybe Sharp don't protect the array so it could be read out again from its firmware.

However, even if we did have the firmware file, it's a huge effort to reverse engineer the programmer's logic from it.

sigh.

[2x4ever]

not necessarily.. it depends on how the gate array is programmed. if it's programmed by Epson, then we're out of luck. If it's a field programmable array and programmed on the board, then maybe just maybe Sharp don't protect the array so it could be read out again from its firmware.

However, even if we did have the firmware file, it's a huge effort to reverse engineer the programmer's logic from it.

sigh.

If i'm understanding a datasheet provided by epson right than it's programmed by Epson.

I've just discovered that FFUART on my pxa250 is working very good at baud rates exceeding 230400. And that's strange because intel says allmost on every page of it's datasheet that you must not exceed this speed. Anyway i'll do more testing and if it will work stable enought than that will be a solution.

[speculatrix]

If i'm understanding a datasheet provided by epson right than it's programmed by Epson.

it's unlikely then that the firmware can be recovered. :-(

I've just discovered that FFUART on my pxa250 is working very good at baud rates exceeding 230400. And that's strange because intel says allmost on every page of it's datasheet that you must not exceed this speed. Anyway i'll do more testing and if it will work stable enought than that will be a solution.

I'd be concerned that this could damage the drivers in the long run, or simply cause overheating in localised hotspots on the CPU and damage it.

I presume from your comments that you've successfully connected a BT module to your SL-C700. What module did you use, and do you have photos of how you connected it?

Paul

This post has been edited by speculatrix: Sep 1 2005, 01:26 PM

[2x4ever]

I'd be concerned that this could damage the drivers in the long run, or simply cause overheating in localised hotspots on the CPU and damage it.

I don't think so. I don't think that increasing speed of a couple of transistors can cause any overheating of the CPU even in localised hotspots. A CPU core isn't located just in the air. It's contained in a package that among other things is distributing a heat over the whole CPU. And since this CPU was not made using 90 nm tehnology not even 130 nm it has a big reserve for overheating. And i've not seen any rising temp. Anyway i'm still testing.

I presume from your comments that you've successfully connected a BT module to your SL-C700. What module did you use, and do you have photos of how you connected it?

I'm using USB Bluetooth Class 1 dongle from Billionton.
http://2x4ever-vpn.compot.ru/zaurus/pics/dongle-zaurus.jpg
I'll post some more images if you want.

[albertr]

I'm using USB Bluetooth Class 1 dongle from Billionton.
http://2x4ever-vpn.compot.ru/zaurus/pics/dongle-zaurus.jpg
I'll post some more images if you want.

I thought that Class 1 device would eat battery faster than Class 2 because of transmit power? Also peak power load is suppoosed to be higher. Where you woud attach that huge antenna?

How fast you are able to run your ffuart? I'm getting 460800 on C1K ffuart (pxa270), but having problems @ 921600.
-albertr

[2x4ever]

I thought that Class 1 device would eat battery faster than Class 2 because of transmit power? Also peak power load is suppoosed to be higher.

Yes i know(My tester shows 75 ma peak power load), but i like it

Where you woud attach that huge antenna?

I'll cut this plastic antenna cover out.

How fast you are able to run your ffuart? I'm getting 460800 on C1K ffuart (pxa270), but having problems @ 921600.

921600 is working but i've not tested it with high traffic yet.

[albertr]

921600 is working but i've not tested it with high traffic yet.

Very interesting... I assume that's with the serial driver from Sharp's 2.4.18 kernel?
And with BCSP protocol (no hardware flow control)?
-albertr

[2x4ever]

921600 is working but i've not tested it with high traffic yet.

Very interesting... I assume that's with the serial driver from Sharp's 2.4.18 kernel?
And with BCSP protocol (no hardware flow control)?
-albertr

Right.

[mikekostousov]

921600 is working but i've not tested it with high traffic yet.

Very interesting... I assume that's with the serial driver from Sharp's 2.4.18 kernel?
And with BCSP protocol (no hardware flow control)?
-albertr

Right.

It looks very interesting. Can you write a guide how to do it? Or take a bit more pictures... I didn't understand, do you have any power control on your bluetooth now, or not?
Thanks.
Mikhail

[2x4ever]

It looks very interesting. Can you write a guide how to do it? Or take a bit more pictures... I didn't understand, do you have any power control on your bluetooth now, or not?
Thanks.
Mikhail

I'll write a guide when i finish. There is nothing to write about for now. I'll provide some more pictures tomorrov (4:35:40 AM here and i'm going to sleep). The only power control i have for now is cutting wires . I still need to find free GPIO pin to do the power control .

[mikekostousov]

I'll write a guide when i finish. There is nothing to write about for now. I'll provide some more pictures tomorrov (4:35:40 AM here and i'm going to sleep).

I am now... I am falling to sleep...

The only power control i have for now is cutting wires

It's not so bad idea If you have the antena outside - you can set a small switcher on the back.
But, by the way, is it possible to use same gpio which are used for the Zaurus syncronization cable? I don't know much about it, but I think an ability... May be, you can use this? For example, if zaurus are in connection with computer there is no ability to change bluetooth power (it can be turned on - if you have Zaurus in the connection, so, perhaps you also have a power supply pluged in), but, when you have cable unpluged you can change power on the bluetooth... You can also take power from synchronization cable...
To albert:
Why you didn't want to create in your C1000 small usb hub and use it for usual usb connection with a usb bluetooth dongle?
Mikhail