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MSP430USBDevelopersPackage_5_20_06_02
Hid_api

Functions

uint8_t USBHID_sendReport (const uint8_t *reportData, uint8_t intfNum)
 
uint8_t USBHID_receiveReport (uint8_t *reportData, uint8_t intfNum)
 
uint8_t USBHID_sendData (const uint8_t *data, uint16_t size, uint8_t intfNum)
 
uint8_t USBHID_receiveData (uint8_t *data, uint16_t size, uint8_t intfNum)
 
uint8_t USBHID_abortReceive (uint16_t *size, uint8_t intfNum)
 
uint8_t USBHID_rejectData (uint8_t intfNum)
 
uint8_t USBHID_abortSend (uint16_t *size, uint8_t intfNum)
 
uint8_t USBHID_getInterfaceStatus (uint8_t intfNum, uint16_t *bytesSent, uint16_t *bytesReceived)
 
uint8_t USBHID_getBytesInUSBBuffer (uint8_t intfNum)
 

Detailed Description

Function Documentation

uint8_t USBHID_abortReceive ( uint16_t *  size,
uint8_t  intfNum 
)

Aborts an Active Recieve Operation on HID Interface.

Parameters
sizeis the number of bytes that were received and are waiting at the assigned address.
intfNumis the data interface for which the receive should be aborted.

Aborts an active receive operation on HID interface intfNum. Returns the number of bytes that were received and transferred to the data location established for this receive operation. The data moved to the buffer up to that time remains valid.

An application may choose to call this function if it decides it no longer wants to receive data from the USB host. It should be noted that if a continuous stream of data is being received from the host, aborting the operation is akin to pressing a "pause" button; the host will be NAK'ed until another receive operation is opened.

See Sec. 7.2 of "Programmer's Guide: MSP430 USB API Stack for CDC/PHDC/HID/MSC" for a detailed discussion of receive operations.

Returns
USB_SUCCEED
uint8_t USBHID_abortSend ( uint16_t *  size,
uint8_t  intfNum 
)

Aborts an Active Send Operation on Data Interface.

Parameters
sizeis the number of bytes that were sent prior to the aboert action.
intfNumis the data interface for which the send should be aborted.

Aborts an active send operation on data interface intfNum. Returns the number of bytes that were sent prior to the abort, in size.

An application may choose to call this function if sending failed, due to factors such as:

  • a surprise removal of the bus
  • a USB suspend event
  • any send operation that extends longer than desired//!
Returns
USB_SUCCEED
uint8_t USBHID_getBytesInUSBBuffer ( uint8_t  intfNum)

Returns the Number of Bytes Waiting in the USB Endpoint Buffer.

Parameters
intfNumis the data interface whose buffer is to be checked.

Returns the number of bytes waiting in the USB endpoint buffer for intfNum. A non-zero value generally means that no receive operation is open by which these bytes can be copied to a user buffer. If the value is non-zero, the application should either open a receive operation so that the data can be moved out of the endpoint buffer, or the data should be rejected (USBHID_rejectData()).

Returns
The number of bytes waiting in this buffer.
uint8_t USBHID_getInterfaceStatus ( uint8_t  intfNum,
uint16_t *  bytesSent,
uint16_t *  bytesReceived 
)

Indicates the Status of the HID Interface.

Parameters
intfNumis the interface number for which the status is being retrieved.
bytesSentIf a send operation is underway, the number of bytes that have been transferred to the host is returned in this location. If no send operation is underway, this returns zero.
bytesReceivedIf a receive operation is underway, the number of bytes that have been transferred to the assigned memory location is returned in this location. If no receive operation is underway, this returns zero.

Indicates the status of the HID interface intfNum. If a send operation is active for this interface, the function also returns the number of bytes that have been transmitted to the host. If a receive operation is active for this interface, the function also returns the number of bytes that have been received from the host and are waiting at the assigned address.

Because multiple flags can be returned, the possible values can be masked together - for example, USBHID_WAITING_FOR_SEND + USBHID_DATA_WAITING.

Returns
Any combination of the following:
  • USBHID_WAITING_FOR_SEND: Indicates that a send operation is open on this interface.
  • USBHID_WAITING_FOR_RECEIVE: Indicates that a receive operation is open on this interface.
  • USBHID_DATA_WAITING: Indicates that data has been received from the host for this interface, waiting in the USB receive buffers, lacking an open receive operation to accept it.
  • USBHID_BUS_NOT_AVAILABLE: Indicates that the bus is either suspended or disconnected. Any operations that had previously been underway are now aborted.
uint8_t USBHID_receiveData ( uint8_t *  data,
uint16_t  size,
uint8_t  intfNum 
)

Receives size Bytes Over HID Interface.

Parameters
datais an array to contain the data received.
sizeis the number of bytes to be received.
intfNumis which data interface to receive from.

Receives size bytes over HID interface intfNum into memory starting at address data. size has no inherent upper limit (beyond being a 16-bit value).

The function may return with USBHID_RECEIVE_STARTED, indicating that a receive operation is underway. The operation completes when size bytes are received. The application should ensure that the data memory buffer be available during the whole of the receive operation.

The function may also return with USBHID_RECEIVE_COMPLETED. This means that the receive operation was complete by the time the function returned.

If the bus is not connected when the function is called, the function returns USBHID_BUS_NOT_AVAILABLE, and no operation is begun. If size is 0, the function returns USBHID_GENERAL_ERROR. If a previous receive operation is already underway for this data interface, the function returns USBHID_INTERFACE_BUSY_ERROR.

USB includes low-level mechanisms that ensure valid transmission of data.

See Sec. 7.2 of "Programmer's Guide: MSP430 USB API Stack for CDC/PHDC/HID/MSC" for a detailed discussion of receive operations.

Returns
Any of the following:
  • USBHID_RECEIVE_STARTED: A receive operation has been successfully started.
  • USBHID_RECEIVE_COMPLETED: The receive operation is already completed.
  • USBHID_INTERFACE_BUSY_ERROR: a previous receive operation is underway.
  • kUSBHID_ busNotAvailable: the bus is either suspended or disconnected.
  • USBHID_GENERAL_ERROR: size was zero, or other error.
uint8_t USBHID_receiveReport ( uint8_t *  reportData,
uint8_t  intfNum 
)

Receives a Report from the Host into reportData.

Parameters
reportDatais an array containing the report.
intfNumis the HID interface over which the data is to be received.

Receives a report from the host into reportData, on interface intfNum. It is expected that the host will organize the report in the format defined by the report descriptor in descriptors.c.

When the function returns USBHID_RECEIVE_COMPLETED, the data has been successfully copied from the USB receive buffers into reportData. If the function returns USBHID_BUS_NOT_AVAILABLE, then the bus has either been disconnected or the device is suspended, allowing no reports to be sent. If the function returns USBHID_GENERAL_ERROR, it means the call failed for unspecified reasons.

The call is intended to be called only when it is known that a report is in the USB buffer. This means it is best called in response to the API calling USBHID_handleDataReceived(), which indicates that a report has been received for interface intfNum.

Returns
Any of the following:
  • USBHID_RECEIVE_COMPLETED
  • USBHID_BUS_NOT_AVAILABLE
  • USBHID_INTERFACE_BUSY_ERROR
uint8_t USBHID_rejectData ( uint8_t  intfNum)

Rejects Data Received from the Host.

This function rejects data that has been received from the host, for interface intfNum, that does not have an active receive operation underway. It resides in the USB endpoint buffer and blocks further data until a receive operation is opened, or until rejected. When this function is called, the buffer for this interface is purged, and the data lost. This frees the USB path to resume communication.

See Sec. 7.2 of "Programmer's Guide: MSP430 USB API Stack for CDC/PHDC/HID/MSC" for a detailed discussion of receive operations.

Returns
USB_SUCCEED
uint8_t USBHID_sendData ( const uint8_t *  data,
uint16_t  size,
uint8_t  intfNum 
)

Initiates Sending of a User Buffer Over HID Interface.

Parameters
datais an array of data to be sent.
sizeis the number of bytes to be sent, starting from address data.
intfNumis which data interface the data should be transmitted over.

Initiates sending of a user buffer over HID interface intfNum, of size size and starting at address data. If size is larger than the packet size, the function handles all packetization and buffer management. size has no inherent upper limit (beyond being a 16-bit value).

In most cases where a send operation is successfully started, the function will return USBHID_SEND_STARTED. A send operation is said to be underway. At some point, either before or after the function returns, the send operation will complete, barring any events that would preclude it. (Even if the operation completes before the function returns, the return code will still be USBHID_SEND_STARTED.)

If the bus is not connected when the function is called, the function returns USBHID_BUS_NOT_AVAILABLE, and no operation is begun. If size is 0, the function returns USBHID_GENERAL_ERROR. If a previous send operation is already underway for this data interface, the function returns with USBHID_INTERFACE_BUSY_ERROR.

USB includes low-level mechanisms that ensure valid transmission of data.

See Sec. 7.2 of "Programmer's Guide: MSP430 USB API Stack for CDC/PHDC/HID/MSC" for a detailed discussion of send operations.

Returns
Any of the following:
  • USBHID_SEND_STARTED: a send operation was successfully started.
  • USBHID_INTERFACE_BUSY_ERROR: a previous send operation is underway.
  • USBHID_BUS_NOT_AVAILABLE: the bus is either suspended or disconnected.
  • USBHID_GENERAL_ERROR: size was zero, or other errorkUSBHID_receiveCompleted.
uint8_t USBHID_sendReport ( const uint8_t *  reportData,
uint8_t  intfNum 
)

Sends a Data Report to the Host.

Parameters
reportDatais an array containing the report.
intfNumis which HID interface the data should be transmitted over.

Sends a pre-built report reportData to the host, on interface intfNum. The report must be organized to reflect the format defined by the report descriptor in descriptors.c.

When the function returns USBHID_SEND_COMPLETE, the data has been written to the USB transmit buffers, and will be transferred to the host in the next polling frame. If the function returns USBHID_BUS_NOT_AVAILABLE, then the bus has either been disconnected or the device is suspended, allowing no reports to be sent. If the function returns USBHID_INTERFACE_BUSY_ERROR, it means the USB buffer for the interface has data in it, suggesting that the host has not yet fetched the previously-loaded report.

Returns
Any of the following:
  • USBHID_SEND_COMPLETE
  • USBHID_BUS_NOT_AVAILABLE
  • USBHID_INTERFACE_BUSY_ERROR