usb test
更新記錄
| item | note |
|---|---|
| 20161026 | 第一版 |
目錄
The Linux USB sub-system
- The host uses a master / slave protocol to communicate with attached USB devices.
- This means that every kind of communication is initiated by the host and devices cannot establish any direct connection to other devices.
USB Devices and Transfer Characteristics
USB host controllers
- Open Host Controller Interface (OHCI, by Compaq)
- Universal Host Controller Interface (UHCI, by Intel)
Data Flow Types
- Data directed from the host to a device is called downstream or OUT transfer.
- The other direction is called upstream or IN transfer
device type different transfer variants are used
Control transfers
standard commands1
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11GET_STATUS
CLEAR_FEATURE
SET_FEATURE
SET_ADDRESS
GET_DESCRIPTOR
SET_DESCRIPTOR
GET_CONFIGURATION
SET_CONFIGURATION
GET_INTERFACE
SET_INTERFACE
SYNCH_FRAMEBulk transfers
- Interrupt transfers
- Isochronous transfers
Enumeration and Device Descriptors
- Whenever a USB device is attached to the bus it will be enumerated by the USB subsystem
- i.e an unique device number (1-127) is assigned and then the device descriptor is read.
Human Interface Devices (HID)
The HID class consists primarily of devices that are used by humans to control the operation of computer systems
- ex
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2Keyboards and pointing devices for example, standard mouse devices, trackballs, and joysticks.
Front-panel controls for example: knobs, switches, buttons, and sliders.
USB Test
kernel config
Linux version 3.4.35_hi3535
記得開啟kernel config(CONFIG_USB_DEVICEFS=y)1
mount -t usbfs none /proc/bus/usb -o devmode=0666
log
- lsusb -v -d 1a86:5523
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71$ sudo lsusb -v -d 1a86:5523
Bus 001 Device 006: ID 1a86:5523 QinHeng Electronics CH341 in serial mode, usb to serial port converter
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 255 Vendor Specific Class
bDeviceSubClass 0
bDeviceProtocol 2
bMaxPacketSize0 8
idVendor 0x1a86 QinHeng Electronics
idProduct 0x5523 CH341 in serial mode, usb to serial port converter
bcdDevice 3.04
iManufacturer 0
iProduct 0
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 39
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 96mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 3
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 1
bInterfaceProtocol 2
iInterface 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x82 EP 2 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0020 1x 32 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0020 1x 32 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 3
Transfer Type Interrupt
Synch Type None
Usage Type Data
wMaxPacketSize 0x0008 1x 8 bytes
bInterval 1
Device Status: 0x0000
(Bus Powered)
example (FT232)
FT232
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15Device Descriptor:
| bNumConfigurations (1)
|---------------------------------------
|
Configuration Descriptor:
| bNumInterfaces (1)
|
|----------------------------
|
Interface Descriptor:
| bNumEndpoints (2)
|
|----------------------------------------------------
| |
Endpoint Descriptor: Endpoint Descriptor:lsusb -v -d 0403:6001
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60$ lsusb -v -d 0403:6001
Bus 001 Device 012: ID 0403:6001 Future Technology Devices International, Ltd FT232 Serial (UART) IC
Couldn't open device, some information will be missing
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.00
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x0403 Future Technology Devices International, Ltd
idProduct 0x6001 FT232 Serial (UART) IC
bcdDevice 6.00
iManufacturer 1
iProduct 2
iSerial 3
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 90mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 255 Vendor Specific Class
bInterfaceSubClass 255 Vendor Specific Subclass
bInterfaceProtocol 255 Vendor Specific Protocol
iInterface 2
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x81 EP 1 IN
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
Endpoint Descriptor:
bLength 7
bDescriptorType 5
bEndpointAddress 0x02 EP 2 OUT
bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data
wMaxPacketSize 0x0040 1x 64 bytes
bInterval 0
其它
FTDI: Simplified Description of USB Device Enumeration
- 名詞定義
USB: Universal Serial Bus
USBDP: USB Data line plus
USBDM: USB Data line minus
USB HOST: The port that controls the USB interface - the master
USB Device: The peripheral that connects to the USB host port - the slave