Specifications

35
35
Standard Request Exercise
 We are a host and we want to generate a request to a device in order to receive
it’s device descriptor
 What values would we need to provide in our SETUP packet data phase?
 Determine the data values we need to send to the device in order for it to respond with
its device descriptor values
0x00122wLength6
0x00002wIndex4
0x01002wValue2
0x061bRequest1
0x801bmRequestType0
ValueSizeFieldOffset
Notes:
1) The device descriptor is 18 bytes long (0x12)
2) The descriptor type is found in the MSB of the wValue field
3) Remember byte ordering
Here is an example of the values we would be parsing for a
Get_Descriptor(DEVICE) request from the host.