Date : 18th Feb 2008
Hello frnds, In my developing I am using USBHID code (available on keil.com) for lpc236x series for USB HID communication. Now any PC have more than 2 USB port. and I want to communicate same two USB hardware(our own hardware ) to same pc on different USB port. Than what change I have to do in this USBHID Example(or USB descriptor file.)
Awaiting for favorable your reply.
Thank you Regard , Suprit patel
Assign unique serial number to each device, which shares the same VID/PID. The serial number is defined in this string descriptor.
usbdesc.c /* USB String Descriptor (optional) */ const BYTE USB_StringDescriptor[] = { ... /* Index 0x42: Serial Number */ 0x1A, /* bLength */ USB_STRING_DESCRIPTOR_TYPE, /* bDescriptorType */ 'D',0, 'E',0, 'M',0, 'O',0, '0',0, '0',0, '0',0, '0',0, '0',0, '0',0, '0',0, '0',0, ...
On the Windows host app, HID devices are listed up by SetupDiEnumDeviceInterfaces( HID_GUID ) Loop through the list and check these items. - VID/PID using HidD_GetAttributes() - Serial Number using HidD_GetSerialNumberString() Then you'll find all of your devices, and also you can distinguish them each other.
In this USB-IF topic, we discussed on counting up all HID composite interfaces on single devices. The procedure is almost same.
"multi-interface device" on USB-IF www.usb.org/.../viewtopic.php
Tsuneo