System.USB.IO.Synchronous

This module provides functionality for performing control, bulk and interrupt transfers.

Documentation

type ReadAction = Size -> Timeout -> IO (ByteString, TimedOut)

Handy type synonym for read transfers.

A ReadAction is a function which takes a Size which defines how many bytes to read and a Timeout. The function returns an IO action which, when executed, performs the actual read and returns the ByteString that was read paired with a flag which indicates whether a transfer timed out.

type WriteAction = ByteString -> Timeout -> IO (Size, TimedOut)

Handy type synonym for write transfers.

A WriteAction is a function which takes a ByteString to write and a Timeout. The function returns an IO action which, when exectued, returns the number of bytes that were actually written paired with an flag which indicates whether a transfer timed out.

type Timeout = Int

A timeout in milliseconds. A timeout defines how long a transfer should wait before giving up due to no response being received. For no timeout, use value 0.

type TimedOut = Bool

True when a transfer timed out and False otherwise.

type Size = Int

Number of bytes transferred.

Control transfers

type ControlAction α = RequestType -> Recipient -> Request -> Value -> Index -> α

Handy type synonym that names the parameters of a control transfer.

data RequestType

Constructors

Standard

Class

Vendor

Instances

Enum RequestType

Eq RequestType

Data RequestType

Read RequestType

Show RequestType

Typeable RequestType

data Recipient

Constructors

ToDevice

ToInterface

ToEndpoint

ToOther

Instances

Enum Recipient

Eq Recipient

Data Recipient

Read Recipient

Show Recipient

Typeable Recipient

type Request = Word8

type Value = Word16

(Host-endian)

type Index = Word16

(Host-endian)

control :: DeviceHandle -> ControlAction (Timeout -> IO ())

Perform a USB control request that does not transfer data.

Exceptions:

• TimeoutException if the transfer timed out.
• PipeException if the control request was not supported by the device
• NoDeviceException if the device has been disconnected.
• Another USBException.

readControl :: DeviceHandle -> ControlAction ReadAction

Perform a USB control read.

Exceptions:

• PipeException if the control request was not supported by the device
• NoDeviceException if the device has been disconnected.
• Another USBException.

readControlExact :: DeviceHandle -> ControlAction (Size -> Timeout -> IO ByteString)

A convenience function similar to readControl which checks if the specified number of bytes to read were actually read. Throws an IOException if this is not the case.

writeControl :: DeviceHandle -> ControlAction WriteAction

Perform a USB control write.

Exceptions:

• PipeException if the control request was not supported by the device
• NoDeviceException if the device has been disconnected.
• Another USBException.

Bulk transfers

readBulk

Arguments

:: DeviceHandle

A handle for the device to communicate with.

-> EndpointAddress

The address of a valid In and Bulk endpoint to communicate with. Make sure the endpoint belongs to the current alternate setting of a claimed interface which belongs to the device.

-> ReadAction

Perform a USB bulk read.

Exceptions:

• PipeException if the endpoint halted.
• OverflowException if the device offered more data, see Packets and overflows in the libusb documentation: http://libusb.sourceforge.net/api-1.0/packetoverflow.html.
• NoDeviceException if the device has been disconnected.
• Another USBException.

writeBulk

Arguments

:: DeviceHandle

A handle for the device to communicate with.

-> EndpointAddress

The address of a valid Out and Bulk endpoint to communicate with. Make sure the endpoint belongs to the current alternate setting of a claimed interface which belongs to the device.

-> WriteAction

Perform a USB bulk write.

Exceptions:

• PipeException if the endpoint halted.
• OverflowException if the device offered more data, see Packets and overflows in the libusb documentation: http://libusb.sourceforge.net/api-1.0/packetoverflow.html.
• NoDeviceException if the device has been disconnected.
• Another USBException.

Interrupt transfers

readInterrupt

Arguments

:: DeviceHandle

A handle for the device to communicate with.

-> EndpointAddress

The address of a valid In and Interrupt endpoint to communicate with. Make sure the endpoint belongs to the current alternate setting of a claimed interface which belongs to the device.

-> ReadAction

Perform a USB interrupt read.

Exceptions:

• PipeException if the endpoint halted.
• OverflowException if the device offered more data, see Packets and overflows in the libusb documentation: http://libusb.sourceforge.net/api-1.0/packetoverflow.html.
• NoDeviceException if the device has been disconnected.
• Another USBException.

writeInterrupt

Arguments

:: DeviceHandle

A handle for the device to communicate with.

-> EndpointAddress

The address of a valid Out and Interrupt endpoint to communicate with. Make sure the endpoint belongs to the current alternate setting of a claimed interface which belongs to the device.

-> WriteAction

Perform a USB interrupt write.

Exceptions:

• PipeException if the endpoint halted.
• OverflowException if the device offered more data, see Packets and overflows in the libusb documentation: http://libusb.sourceforge.net/api-1.0/packetoverflow.html.
• NoDeviceException if the device has been disconnected.
• Another USBException.