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dkersten:

But can you send any kind of analog or optical data through that interface?  I can see keystrokes easy enough, but transmitting axes from various analog devices is a whole other animal.  Particular considering that most modern "mouse" type devices are no longer analog in nature.  Just wondering on this, I have no intention of trying to come up with a remote control panel myself. 

ark_ader:


--- Quote from: dkersten on July 16, 2014, 11:57:01 am ---But can you send any kind of analog or optical data through that interface?  I can see keystrokes easy enough, but transmitting axes from various analog devices is a whole other animal.  Particular considering that most modern "mouse" type devices are no longer analog in nature.  Just wondering on this, I have no intention of trying to come up with a remote control panel myself.

--- End quote ---

I am not sure about analogue controls like thumb pads or mouse but it is a nice experiment to conduct.  I have a BT gamepad and I will try this out tonight as it connects to the android device.  I tried using the MK808b but I could not get a reliable power source as this is a wireless operation, so I have a Galaxy Note 2 that can keep a good charge and do the same job with an OTG USB connection.  I looked at using the my Galaxy S phone with BluezIME but was unsure if Honeycomb was supported with DroidMote for Splashtop for this scenario.  IF it does then there is a possibility of having a full solution for less than £50 or whatever the Samsung Galaxy S goes for these days.

Edit:  I was just looking at PL1's signature image of one CP and HTPC and two displays.  If both these displays had a MK808 attached and were mirrored display from the HTPC, all you would have to do is assign an IP address to the Phone/Tablet and  that would reduce the effort by half.

SavannahLion:

Not to steal away the thread.


--- Quote from: MonMotha on July 11, 2014, 11:31:49 pm ---
--- Quote from: corndwg01 on July 11, 2014, 11:02:47 pm ---What is boot protocol and why should I be concerned?

--- End quote ---

"Boot protocol" mode is a stripped down subset of USB HID (the overarching standard for USB "Human Interface Devices" like keyboards, mice, joysticks, gamepads, etc.) designed to make it easy to support keyboards and mice with very limited code in the BIOS.  This was very important back before operating systems had widespread support for USB, and it's still sometimes needed in order for the keyboard to be usable in the "BIOS setup" type screens, though some new BIOSes and EFI systems include full HID support.  Windows 95 OSR2 also only supported this mode, but every OS since Windows 98 (though somewhat limited), including Windows 2000 and newer, has had full HID support.

This mode has a limitation of 6 simultaneous keypresses on keyboards.  If you exceed 6 simultaneous keys pressed, the keyboard will indicate "rollover".

It is not REQUIRED that all keyboards run in this mode, but most conventional keyboards do so that they have maximal compatibility.  The USB HID standard clearly intended for almost all keyboards to implement alternate settings that would remove the 6-key limitation, but in practice no cheap keyboard does, and it would require special "drivers" on Windows to support switching to that mode, anyway.  Some high-end keyboards, like Das Keyboard, get around this by having a special hotkey sequence to toggle between boot protocol mode and a mode with no (or a very high) limit on simultaneous keypresses.  Most arcade encoder boards using specialized firmware, rather than off-the-shelf keyboard controller silicon, never run in this mode, since rarely does anybody want to us Windows 95 OSR2 or set up their PC's BIOS settings using their arcade control panel.

Support for an arbitrary number of simultaneous keypresses is commonly called "Full N-key Rollover".  Contrary to what seems to be somewhat common belief, this is fully possible with USB, but you do have to give up boot protocol mode to do it.

Super annoyingly, a lot of PS/2 to USB adapters not only are restricted to boot protocol mode (and hence 6 simultaneous keypresses), they also cancel all active keys after some lengthy-but-easily-encountered period.  This makes them unsuitable for gaming.

There is a similar "boot protocol" mouse profile.  This is not so common these days, since it has an arbitrary limitation on the number of buttons and axes that many common gaming mice, etc. exceed, and nobody really cares about having mouse support when running their BIOS setup.  It was mostly important for a couple years where USB mice were starting to become popular (supplanting PS/2 and serial mice) but OS support hadn't caught up yet.  In those cases, the BIOS emulated a PS/2 mouse in software, and generally it only supported the boot protocol mode.

--- End quote ---

Interestingly, if you read the Adafruit Bluefruit page, you'll find this little blurb:

--- Quote ---When a switch is pressed, a KEYDOWN command is sent, when it is release, a matching KEYUP goes out. You can have up to 6 switches pressed at once and it will be like they were pressed all at the same time. 6 is a strict limit of Bluetooth.

--- End quote ---

I have yet to see any sort of documented 6 key limitation imposed via BT. Everything I found using my SearchFU is anecdotal so I suspect the BT limit is directly tied into the USB boot protocol. AFAIK, Adafruit haven't released the source code for their Bluefruit so I have to wonder if the firmware is derived from some Vanilla reference leaving their device in a reduced compatibility mode. Any insight on that?

corndwg01:

That's right, I found out the 6 key limit is a USB limit.  I heard back from the handheldsci.com guy and that's what he told me.

PL1:


--- Quote from: corndwg01 on August 01, 2014, 08:49:03 am ---That's right, I found out the 6 key limit is a USB limit.  I heard back from the handheldsci.com guy and that's what he told me.

--- End quote ---
His product may have that limit, but that doesn't make it a USB limit.

I'd trust SavannahLion, Andy Warne, and the KADE team over "the handheldsci.com guy" on this, especially since Andy and the KADE team both sell a variety of products that easily exceed that "USB limit".   :lol


Scott

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