Hardware Reference
In-Depth Information
bNumConfigurations
des Device Descriptors (beginnend mit 1, für nur eine Konfi-
guration).
Datenfeld
Wert
Bedeutung
bmRequestType
10000000
Standard, Device to Host, Recipient: Device
bRequest
00000110
GET_DESCRIPTOR
wValue
0x0200
Typ: Configuration Descriptor
wIndex
0x0000
Keine Endpoint- oder Interface-Adresse
wLength
*
Erwartete Anzahl von Bytes
;******************************************************************************
; USB Standard Request: GET_DESCRIPTOR_CONFIGURATION
;******************************************************************************
GET_DESCRIPTOR_CONFIGURATION
movlw UPPER ConfigurationDescriptor
movwf TBLPTRU
movlw HIGH ConfigurationDescriptor
movwf TBLPTRH
movlw LOW ConfigurationDescriptor
movwf TBLPTRL
call
IN_Descriptor
bra
transtest_over_ctl_out
Aufbau des Configuration Descriptors vom Beispielgerät
ConfigurationDescriptor
; Length:
DB
.39
;packet length (lower byte)
DB
.0
;packet length (higher byte)
; USB-part:
DB .9 ;bLength size of descriptor
DB 0x02 ;bDescriptorType $02 is Configuration Descriptor
DB .39 ;wTotalLength (lower byte)
DB 0x00 ;wTotalLength (higher byte)
DB 0x01 ;bNumInterfaces
DB 0x01 ;ConfigurationValue
DB 0x04 ;iConfiguration string index
DB 0x80 ;bmAttributes
DB .100 ;MaxPower
;(InterfaceDescriptor:)
DB
.9
;bLength size of descriptor
DB
0x04 ;bDescriptorType $04 is Interface Descriptor
DB
0x00 ;bInterfaceNumber
DB
0x00 ;bAlternateSetting
DB
0x03 ;bNumEndpoints
DB
0xFE ;bInterfaceClass $FE is
DB
0x03 ;bInterfaceSubClass ($03 is USB488 interface)
DB
0x01 ;bInterfaceProtocol ($01 us USB488 interface protocol)
DB
0x05 ;iInterface string index
