Re: [chromium-discuss] USB devices with multiple endpoints and Chrome

[Primiano Tucci]

[moving discussion to web...@chromium.org]

If you haven't written any code yet and are getting started now please skip this section and goto part2 :)

The extension-only chrome.usb API seems to support multiple endpoints on the same vid&pid pair if you look at https://developer.chrome.com/apps/usb#method-claimInterface

Having said that, keep in mind that, as announced in https://blog.chromium.org/2016/08/from-chrome-apps-to-web.html, Chrome Apps themselves are slowly sunsetting (I think you won't be able to publish a new one, only upgrade an existing one) and the general guidelines is to look at new HTML5 APIs, not extension APIs.

part2:

If you are starting a new project from scratch, I think you might want to take a look to the shiny new WebUSB API

That one seems to support multiple endpoints (see here). Also keep in mind that, as announced in Intent to Continue Experimenting: WebUSB WebUSB is currently behind Origin Trials. 

The webusb@ mailing list might be more appropriate for more specific questions like this.

Regards,

Primiano

On Mon, Feb 20, 2017 at 7:24 AM George Frueh <gtf...@gmail.com> wrote:

Good day,

I have developed a USB composite device (using a Cypress Semiconductor chip and their emulator/tools) that uses Endpoint 0 for control and Endpoints 1, 2, 3 & 4 for Interrupt transfers. The device works fine under Windows and the application program for the device was written in VB6. I'm trying to rewrite the application program so that the device can be used on a Chromebook. I am using Chrome Dev Editor for this task and am relatively new to Javascript/HTML, so my learning is on a couple of different fronts.

I've also developed a more modest USB device that only uses two Endpoints - 1 & 2. I have been having better luck with this device on my Chromebook as I tinker around. My biggest question is, does the Chromebook  (and Chrome OS) have the ability to handle a Composite USB device setup with four Endpoints? If so, does anyone have any links they can pass my way for my further studies?

Thanks in advance.

George

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[Reilly Grant]

Both the chrome.usb and WebUSB APIs support composite devices with multiple endpoints. Make sure that you've claimed the interfaces containing these endpoints before trying to send transfers to them.

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