Hi Peter! I am trying to integrate IOIO in the ROSJava framework. Can you 
please give me some pointers on how to go about it? 

Thanks. :)

On Monday, February 18, 2013 6:36:07 AM UTC+1, Ytai wrote:
>
> What people typically do is implement all the low-latency stuff on the MCU 
> and expose a higher-level, less latency-sensitive protocol over USB.
>
>
> On Thu, Feb 14, 2013 at 8:56 AM, Dan Christian <[email protected] 
> <javascript:>> wrote:
>
>> @Peter,
>> Yes, "grok" means to understand fully.  I think it came from an old
>> Heinlein novel.
>>
>> There is a fundamental timebase in full speed (12mbps) USB of 1ms.  If
>> you need to do round trip operations (e.g. set a pin then read a pin),
>> you have to expect 2+ms.  Many of the IOIO primitives are designed to
>> stream data, so the one way latency should be around 1ms.
>>
>> High speed (480mbps) USB can theoretically cut this by a factor of 8.
>> I don't know of any microcontrollers that implement high speed.  It's
>> more the realm of FPGAs, but they don't have the nice IO structures of
>> the PIC.
>>
>> The fastest would be a PCI/PCIe card, but that's a very different
>> thing than the original goal of the IOIO.  You can buy such a thing
>> from various sources, but the cost is hundreds of dollars.
>>
>> -Dan
>>
>> On Wed, Feb 13, 2013 at 11:23 PM, Peter <[email protected] 
>> <javascript:>> wrote:
>> >
>> > I'm still feeling my way around this problem.
>> >
>> > From what I understand I agree that there will still be the comms pipe 
>> to
>> > the PIC which governs performance so any abstraction of additional pins
>> > would add to the overhead.
>> >
>> > I'm not looking at using android or windows, but ubuntu because the
>> > libraries I would like to use the ioio with are in roscpp and rospy 
>> which
>> > are the corelibries and run in linux.
>> >
>> > The particular libraries are run as plugins to an executable 
>> representing a
>> > rosnode that is the hardware. These plugins are passed an instance of 
>> the
>> > hardware, an object describing and exposing the hardware functionality 
>> of
>> > the robot which is based on the etherCAT control hardware. What I was 
>> hoping
>> > to do was to create a cpp object that exposes the ioio functionality in 
>> the
>> > same way.
>> >
>> > If there's no benefit in performance in breaking things down the way I
>> > initially proposed, then I can still use an instance of the ioio that 
>> has
>> > the same functionality that is exposed in the IOIOlib. Is this interface
>> > protocol available somewhere?
>> >
>> > cheers
>> >
>> >
>> > Peter
>> >
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