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Fix typos, more precise example for configurations.

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This commit is contained in:
Sebastian Zagrodzki
2017-06-13 10:40:01 +02:00
parent 688cb291dd
commit b709988501
1 changed files with 10 additions and 9 deletions
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19
usb.go
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@@ -20,25 +20,26 @@ A Short Tutorial
A Context manages all resources necessary for communicating with USB A Context manages all resources necessary for communicating with USB
devices. devices.
Through the Context users can iterate over available USB devices, Through the Context users can iterate over available USB devices.
The USB standard defines a mechanism of discovering USB device functionality The USB standard defines a mechanism of discovering USB device functionality
through a mechanism of descriptors. After the device is attached and through descriptors. After the device is attached and
initialized by the host stack, it's possible to retrieve it's descriptor initialized by the host stack, it's possible to retrieve its descriptor
(the device descriptor). It contains elements such as product and vendor IDs, (the device descriptor). It contains elements such as product and vendor IDs,
bus number and device number (address) on the bus. bus number and device number (address) on the bus.
In gousb Device struct represents the USB device, and Device.Desc In gousb, the Device struct represents a USB device. The Device struct’s Desc
contains all the information known about the device. field contains all known information about the device.
Among other information in the device descriptor is a list of configuration Among other information in the device descriptor is a list of configuration
descriptors, accessible through Device.Desc.Configs. descriptors, accessible through Device.Desc.Configs.
USB standard allows one physical USB device to switch between different The USB standard allows one physical USB device to switch between different
sets of behaviors, or working modes, by selecting one of the offered configs sets of behaviors, or working modes, by selecting one of the offered configs
(each device has at least one). (each device has at least one).
This allows the same device to sometimes present itself as e.g. a 3G modem, This allows the same device to sometimes present itself as e.g. a 3G modem,
and sometimes a flash drive. Configs are mutually exclusive, each device and sometimes as a flash drive with the drivers for that 3G modem.
Configs are mutually exclusive, each device
can have only one active config at a time. Switching the active config performs can have only one active config at a time. Switching the active config performs
a light-weight device reset. Each config in the device descriptor has a light-weight device reset. Each config in the device descriptor has
a unique identification number. a unique identification number.
@@ -48,7 +49,7 @@ It returns a Config struct that represents the device in this particular configu
The configuration descriptor is accessible through Config.Desc. The configuration descriptor is accessible through Config.Desc.
A config descriptor determines the list of available USB interfaces on the device. A config descriptor determines the list of available USB interfaces on the device.
Each interface is a virtual device within the physical USB device and it's active Each interface is a virtual device within the physical USB device and its active
config. There can be many interfaces active concurrently. Interfaces are config. There can be many interfaces active concurrently. Interfaces are
enumerated sequentially starting from zero. enumerated sequentially starting from zero.
@@ -58,7 +59,7 @@ interface level. Each interface can have only a single alternate setting
active at any time. Alternate settings are enumerated sequentially starting from active at any time. Alternate settings are enumerated sequentially starting from
zero. zero.
In gousb an interface and it's alternate setting can be selected through In gousb an interface and its alternate setting can be selected through
Config.Interface(num, altNum). The Interface struct is the representation Config.Interface(num, altNum). The Interface struct is the representation
of the claimed interface with a particular alternate setting. of the claimed interface with a particular alternate setting.
The descriptor of the interface is available through Interface.Setting. The descriptor of the interface is available through Interface.Setting.