Documentation
¶
Overview ¶
Package usb contains helpers for building USB descriptors and data.
Index ¶
Constants ¶
const ( DeviceDescType = 0x01 ConfigDescType = 0x02 InterfaceDescType = 0x04 EndpointDescType = 0x05 HIDDescType = 0x21 ReportDescType = 0x22 )
USB descriptor type constants
const ( DeviceDescLen = 18 ConfigDescLen = 9 InterfaceDescLen = 9 EndpointDescLen = 7 HIDDescLen = 9 )
Descriptor lengths in bytes (fixed values from USB spec)
Variables ¶
This section is empty.
Functions ¶
func EncodeStringDescriptor ¶
EncodeStringDescriptor converts a UTF-8 string to a USB string descriptor byte array. The resulting descriptor has the format:
Byte 0: bLength (total descriptor length) Byte 1: bDescriptorType (0x03 for string) Bytes 2+: UTF-16LE encoded string
Types ¶
type ConfigHeader ¶
type ConfigHeader struct {
WTotalLength uint16 // LE, to be patched after building
BNumInterfaces uint8
BConfigurationValue uint8
IConfiguration uint8
BMAttributes uint8
BMaxPower uint8
}
ConfigHeader represents the USB configuration descriptor header (9 bytes).
func (ConfigHeader) Write ¶
func (h ConfigHeader) Write(b *bytes.Buffer)
type Descriptor ¶
type Descriptor struct {
Device DeviceDescriptor
Interfaces []InterfaceConfig
Strings map[uint8]string
}
Descriptor holds all static descriptor/config data for a device.
func (Descriptor) Bytes ¶
func (d Descriptor) Bytes() []byte
Bytes returns the binary representation of the DeviceDescriptor with BLength auto-filled.
type Device ¶
type Device interface {
// HandleTransfer processes a non-EP0 transfer (interrupt/bulk).
// ep is the endpoint number (without direction). dir is protocol.DirIn or protocol.DirOut.
// For IN transfers, return the payload to send; for OUT, consume 'out' and return nil.
HandleTransfer(ep uint32, dir uint32, out []byte) []byte
GetDescriptor() *Descriptor
}
Device is the minimal interface a device must implement. It only handles non-EP0 (interrupt/bulk) transfers.
type DeviceDescriptor ¶
type DeviceDescriptor struct {
BcdUSB uint16 // LE
BDeviceClass uint8
BDeviceSubClass uint8
BDeviceProtocol uint8
BMaxPacketSize0 uint8
IDVendor uint16 // LE; may get overridden
IDProduct uint16 // LE; may get overridden
BcdDevice uint16 // LE
IManufacturer uint8
IProduct uint8
ISerialNumber uint8
BNumConfigurations uint8
Speed uint32 // USB speed: 1=low, 2=full, 3=high, 4=super
}
DeviceDescriptor represents the standard USB device descriptor. BLength is computed dynamically; BDescriptorType is implied DeviceDescType.
type EndpointDescriptor ¶
type EndpointDescriptor struct {
BEndpointAddress uint8
BMAttributes uint8
WMaxPacketSize uint16 // LE
BInterval uint8
}
EndpointDescriptor (7 bytes) for each endpoint.
func (EndpointDescriptor) Write ¶
func (e EndpointDescriptor) Write(b *bytes.Buffer)
type HIDDescriptor ¶
type HIDDescriptor struct {
BcdHID uint16 // LE
BCountryCode uint8
BNumDescriptors uint8
ClassDescType uint8 // 0x22 (report)
WDescriptorLength uint16 // LE, report descriptor length
}
HIDDescriptor (class descriptor, 0x21) with one subordinate report descriptor (0x22).
func (HIDDescriptor) Write ¶
func (h HIDDescriptor) Write(b *bytes.Buffer)
type InterfaceConfig ¶
type InterfaceConfig struct {
Descriptor InterfaceDescriptor
Endpoints []EndpointDescriptor
HIDDescriptor []byte // optional HID class descriptor (0x21)
HIDReport []byte // optional HID report descriptor (0x22)
VendorData []byte // optional vendor-specific bytes
}
InterfaceConfig holds all descriptors for a single interface for bus management.
type InterfaceDescriptor ¶
type InterfaceDescriptor struct {
BInterfaceNumber uint8
BAlternateSetting uint8
BNumEndpoints uint8
BInterfaceClass uint8
BInterfaceSubClass uint8
BInterfaceProtocol uint8
IInterface uint8
}
InterfaceDescriptor (9 bytes) for each interface altsetting.
func (InterfaceDescriptor) Write ¶
func (i InterfaceDescriptor) Write(b *bytes.Buffer)
type ReportDescriptor ¶
type ReportDescriptor struct {
Data []byte
}
ReportDescriptor is a container for HID report descriptor bytes (0x22). Builders can populate Data to emit via Bytes().
func (ReportDescriptor) Bytes ¶
func (r ReportDescriptor) Bytes() []byte
Source Files