Approximately 3 months ago i defined a usb project myself
My chip was PDIUSBD12 from Philips Company
The hardware was O.K and I Could Initialize D12,Change Output Freq ..... also Good Link was Shined as Blink
Those days the project was stopped,But three days ago i continue the projet again.
After Initializing the chip The Host send first Descriptor request Just like this:
EP0_Control_out_Buffer: 80H 06H 00H 01H 00H 00H 40H 00H
Now the device(MCU or Chip) must send a standard Device descriptor According to this request
I know this and i know it must be 18 byte for example like this:

WRITE_TO_BUFFER_DEVICE_DESCRIPTORS:
MOV bLength,#12H
MOV bDescriptorType,#01H
MOV bcdUSBL,#10H
MOV bcdUSBH,#01H
MOV bDeviceClass,#00H
MOV bDeviceSubclass,#00H
MOV bDeviceProtocol,#00H
MOV bMaxPacketSize,#08H
MOV idVendorH,#34H
MOV idVendorL,#12H
MOV idProductH,#01H
MOV idProductL,#00H
MOV bcdDeviceH,#00H
MOV bcdDeviceL,#01H
MOV iManufacture,#01H
MOV iProducts,#02H
MOV iSerialNumber,#03H
MOV bNumConfigurations,#01H
CALL WRITE_DEVICE_DESCRIPTORS
RET

But i don't know When and How i must send The Descriptor to the Host?
Do i must send descriptor in the next control in interrupt?
Or no i must send it immediately after extracting the request and acknowledging the host at end of control out interrupt?
I read Firmware Programming Guide for PDIUSBD12 From Philips
exactly and i implemented what it said, but i hadn't any progress in process,Also i found some source code in C And Assembly,I read them But USB Device Not Recognized is only message that host shows in taskbar


I extremely appreciate From any helpful advice and comment
Best Regards
Mehdi