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14

the minimum a port needs to provide is 100mA so all usb devices can assume that is available if the device needs anything more than that it needs to negotiate it with the port, the standard 2.0 port can handle 500 mA there is an exception with dedicated charging ports which don't have any electronics to negotiate the draw and are recognizable by a shorted ...


5

You can get 166Hz.. that's interesting as I thought the default polling rate for USB was 125Hz. Still, you'll possibly need to modify your kernel, drivers/usb/input/hid-core.c - set the polling rate there. There's a fair bit of info on the internet about updating mouse polling rates to 1000Hz (those gamers....) either with a tweak to the configuration. It ...


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Interrupts are a hardware mechanism similar to events. Whenever a specific condition arises in the physical world (e.g. data arriving on USB), a line switches from one level to the other. This is an interrupt request. The CPU is built to detect this change and to respond by jumping to an Interrupt Service Routine. This routine in turn generates a software ...


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USB is quite complicated because various parts of the protocol may be implemented in hardware depending upon the platform being used. It might be easier to consider something a little simpler, perhaps a serial port controller. The precise series of actions that are performed will depend upon the processor interrupt handling mechanism (some processors are ...


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Automatic Detection of USB Port vs Wall Adapter Power When a device is connected to an actual USB port, the system detects a USB host ID and can then set the battery charge controller to a level at or below 500 mA to match the current capacity available from most USB ports Using a USB controller to detect and set the charger I/C for USB ...


3

500Hz through USB, assuming 8 or 16 bit data, should be no problem. I've worked on an application that sampled 4 16 bit channels at 8kHz, and I didn't even have to give it any consideration to make it read that fast. How are you hitting your 166Hz ceiling? Are you at 100% cpu usage on the client? Are you hitting 100% utilization on your USB device? What USB ...


2

File extensions normally tell the end user and the operating system what type of file it is. In your case, maybe the file extension was hidden by windows(in this case, it is a SYS file), or maybe it was flagged with a "System" File Attribute(Thanks to Hellion for the added info). If your case was the former, Here is a description for the SYS File Format for ...


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Definitely stay away from Java applets and Silverlight. Both are tricky for users, error-prone, and their future is uncertain at best. The only tricky part is the client. For client, I'd take a well-supported cross-platform language. Unfortunately, you can't be sure that a runtime for such a language is readily available on a client machine. So bring it ...


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A front end would get the user input and then write to the pickit2 using these command line interfaces. This is basically your answer, but You need a Web Exposed front End. That means a web-server running on the same machine as the USB Device. This way it's Server side code - Local to the USB Device controlling the hardware. (The answers in you ...



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