Transport Layer Driver References
The following table shows the functions used to write your own transport layer driver on Windows CE.
| Function | Description |
|---|---|
| HCI_OpenConnection | This function is used to set up, initialize, and establish a connection to the hardware.
It returns TRUE when a connection to the hardware is successfully established. This is a blocking function. |
| HCI_ReadHciParameters | This function returns the following information about the hardware: version, maximum packet size, and timeout. |
| HCI_ReadPacket | This function allocates an empty buffer (where the size is requested during HCI_ReadHciParameters time) and fills this with an incoming packet, if any.
This function returns with a packet type and error condition. This is a blocking function. It blocks while doing a read. If an error is returned, the Bluetooth protocol stack will be shut down. This function must unblock and return an error if HCI_CloseConnection is called. |
| HCI_WritePacket | This function allocates an empty buffer with pre-allocated spaces for packet headers and trailers, which are requested by HCI_ReadHciParameters.
The HCI_WritePacket function blocks while writing the packet. It returns the packet type and buffer. If an error is returned, the stack will be shut down. This function must unblock and return an error if HCI_CloseConnection is called. |
| HCI_CloseConnection | Calling this function will unblock reads and writes, un-initialize the hardware, and free up any allocated resources including buffers. If a driver is in DLL, it may be unloaded when this function returns. |
| HCI_SetCallback | If hardware removal or insertion is detected, the transport calls the function provided by the upper layer. |
| HCI_StartHardware | This function calls the callback provided by the stack to simulate hardware insertion. |
| HCI_StopHardware | This function calls the callback provided by the stack to simulate hardware removal. |
Data Transfers
To avoid data copying, the protocol stack uses two static buffers: one for read and the other for write. These buffers are given to the HCI_ReadPacket and HCI_WritePacket functions, respectively.
The data transfer structure is organized in such a way that headers can be easily pre-allocated on the way down or stripped on the way up.
See Also
Last updated on Tuesday, May 18, 2004
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