PORTS Forum
Ports and Interfaces => USB => Topic started by: Selva on August 09, 2014, 09:20:35 am
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I need to access the data from usb isochronous device which is configured under vendor specific class.
please find the attachment for device details taken using usb view .
I am trying to access the device via generic Isochronous Driver calls of VOS(vinculum os ) .
I am able to get the IN & OUT endpoint via the corresponding IO calls ,
I am facing few problem in reading & writing data in isochronous transfer .
I am able to write to Isochronous out endpoints using isochronous transfer block.
I got the return status USBHOST_PENDING .
After writing I am polling the condition code which is not changing .
Is there anything needs to be done before writing the data to OUT endpoint
I am doing in the following way
1. Get the handle using VOS_IOCTL_USBHOST_DEVICE_FIND_HANDLE_BY_VID_PID
2. Get control endpoint VOS_IOCTL_USBHOST_DEVICE_GET_CONTROL_ENDPOINT_HANDLE
3. Get isochronous IN endpoint using VOS_IOCTL_USBHOST_DEVICE_GET_ISO_IN_ENDPOINT_HANDLE
4. Get isochronous(http://) OUT endpoint using VOS_IOCTL_USBHOST_DEVICE_GET_ISO_OUT_ENDPOINT_HANDLE
5. After getting isochronous out I have formed isochronous transfer block .
6. Then I am writing data to isochronous out endpoints.
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I don't have specific suggestions, but maybe John Hyde's USB Design by Example would be helpful:
http://www.ftdichip.com/Products/ICs/VNC2.htm
Some info here as well:
http://www.ftdichip.com/Support/Documents/AppNotes/AN_164_Vinculum_II_USB_Slave_Writing_A_Function_Driver.pdf