我正在使用覆盆子上的一个小Python脚本与外部设备进行交互 . 外部设备有RS232和USB端口,我通过USB端口使用它 .
lsusb显示: Bus 001 Device 004: ID 0665:5161 Cypress Semiconductor USB to Serial
所以我想嵌入式设备中的USB端口内部有一个USB转串口转换器 .
直到那里一切都很好,除了当我通过PyUSB打开设备时,我只能获得IN endpoints (0x81)而不是OUT endpoints .
所以我决定通过lsusb -v进行检查:
Bus 001 Device 004: ID 0665:5161 Cypress Semiconductor USB to Serial
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 1.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 8
idVendor 0x0665 Cypress Semiconductor
idProduct 0x5161 USB to Serial
bcdDevice 0.02
iManufacturer 3 (error)
iProduct 1 (error)
iSerial 0
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 34
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0xa0
(Bus Powered)
Remote Wakeup
MaxPower 100mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 1
bInterfaceClass 3 Human Interface Device
bInterfaceSubClass 0 No Subclass
bInterfaceProtocol 0 None
iInterface 0
HID Device Descriptor:
bLength 9
bDescriptorType 33
bcdHID 1.11
bCountryCode 0 Not supported
bNumDescriptors 1
bDescriptorType 34 Report
wDescriptorLength 27
Report Descriptor: (length is 27)
Item(Global): Usage Page, data= [ 0x00 0xff ] 65280
(null)
Item(Local ): Usage, data= [ 0x01 ] 1
(null)
Item(Main ): Collection, data= [ 0x01 ] 1
Application
Item(Local ): Usage, data= [ 0x02 ] 2
(null)
Item(Global): Logical Minimum, data= [ 0x00 ] 0
Item(Global): Logical Maximum, data= [ 0xff 0x00 ] 255
Item(Global): Report Size, data= [ 0x08 ] 8
Item(Global): Report Count, data= [ 0x08 ] 8
Item(Main ): Input, data= [ 0x82 ] 130
Data Variable Absolute No_Wrap Linear
Preferred_State No_Null_Position Volatile Bitfield
Item(Local ): Usage, data= [ 0x02 ] 2
(null)
Item(Global): Report Count, data= [ 0x08 ] 8
Item(Main ): Output, data= [ 0x82 ] 130
Data Variable Absolute No_Wrap Linear
Preferred_State No_Null_Position Volatile Bitfield
Item(Main ): End Collection, data=none
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 12
Device Status: 0x0000
(Bus Powered)
只有一个配置,一个接口,一个 endpoints ,并标记为IN . 那可能吗?
提前致谢!
1 回答
这个提示是:
HID通过中断 endpoints 将数据传输到PC(IN) . 反向使用默认控制 endpoints (EP0) .
虽然情况可能如此,但它使用了一种不寻常的配置 . HID协议不需要PC上的(OEM)驱动程序,但对数据速率的限制要低得多 - 这对于像UPS这样的设备是可以的 .
TL;DR 只需像使用pyUSB的任何其他HID设备一样访问设备,并使用OUT(Pi =>设备)方向的控制消息 .