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]

Umm, I wasn't thinking about using the same serial port for both bluetooth and serial connections. How that could be done?

I believe that charging LED control is only used in the kernel code. I might be wrong, but it doesn't look like this LED is used in QT/Qtopia. If so, it shouldn't be hard to modify this code to blink twice or whatever.
-albertr

[2x4ever]

Umm, I wasn't thinking about using the same serial port for both bluetooth and serial connections. How that could be done?

I believe that charging LED control is only used in the kernel code.  I might be wrong, but it doesn't look like this LED is used in QT/Qtopia. If so, it shouldn't be hard to modify this code to blink twice or whatever.
-albertr

It cannot be used for both bt and serial connections at the same time of course. But when BT is switched off a use of this serial port for other things shouldn't be a problem. However it may require some diodes to be soldered.

[speculatrix]

Umm, I wasn't thinking about using the same serial port for both bluetooth and serial connections. How that could be done?

It cannot be used for both bt and serial connections at the same time of course. But when BT is switched off a use of this serial port for other things shouldn't be a problem. However it may require some diodes to be soldered.

why not steal the IRDA serial lines? are they actually any use at all?

[2x4ever]

Umm, I wasn't thinking about using the same serial port for both bluetooth and serial connections. How that could be done?

It cannot be used for both bt and serial connections at the same time of course. But when BT is switched off a use of this serial port for other things shouldn't be a problem. However it may require some diodes to be soldered.

why not steal the IRDA serial lines? are they actually any use at all?

Yes. I'm using irda time to time. Not all of my friends have bluetooth enabled hardware.
But actualy we can share irda serial line with bluetooth.

[mikekostousov]

Umm, I wasn't thinking about using the same serial port for both bluetooth and serial connections. How that could be done?

It cannot be used for both bt and serial connections at the same time of course. But when BT is switched off a use of this serial port for other things shouldn't be a problem. However it may require some diodes to be soldered.

why not steal the IRDA serial lines? are they actually any use at all?

Yes. I'm using irda time to time. Not all of my friends have bluetooth enabled hardware.
But actualy we can share irda serial line with bluetooth.

Ok.. If you turned external power on, the power LED is turned on and you will take bluetooth power on and all irda hardware down...
Is it ok?

[2x4ever]

Ok.. If you turned external power on, the power LED is turned on and you will take bluetooth power on and all irda hardware down...
Is it ok?

No. The power LED is controlled by kernel so we can track the moment when external power cord is connected and turn on the power LED twice quickly. The pull-down capacitor will not allow BT to be turned on during this procedure. The only place where we can't track the moment of applying power is when device is in sleep mode or is switched off. But IRDA transiver is switched of at this moment too so this is not an issue.