Fifo buffer

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Detailed Description

Buffers structures implemented in uSmartX are standard cyclic fifo buffers with some additional features. Basicaly they are very similar to mailboxes with the exception that a tasks could't pend on it when they are requesting or putting data into it. The buffer strucure is not fixed but, it is defined at compile time, particulary the buffer size and the element size. Other parameters of the buffer can be changed in run time, although some default values are entered at compile time.

Buffers have two event functions associated. One of them is invoked when the buffer fills to a certain level and the second one is executed when the buffer contains unread data which is older that the specified timeout.

Defines
#define	BUF_CREATE(name, n, data_size)
	Create a cyclic fifo buffer.
Functions
STATUS	BUF_Put (HANDLE *ph, void *pdata)
	Put data into the buffer.
STATUS	BUF_Get (HANDLE *ph, void *pdata)
	Get data from buffer.
void	BUF_Flush (HANDLE *ph)
	Empty buffer.
uint16	BUF_Querry (HANDLE *ph)
	Querry buffer.
void	BUF_AppendToutFxn (HANDLE *ph, uint16 timeout, STATUS(*pfxn)(uint8 evt, void *parg1, void *parg2))
	Set buffer timeout.
void	BUF_AppendTrgFxn (HANDLE *ph, uint16 trigger, STATUS(*pfxn)(uint8 evt, void *parg1, void *parg2))
	Set buffer trigger level.

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Define Documentation

#define BUF_CREATE (  name, n, data_size   )

Create a cyclic fifo buffer. This macro creates a cyclic fifo buffer structure and allocates needed memory. Parameters: name  name of the buffer n  number of data containers data_size  data size of each entry Examples: buffer.c.

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Function Documentation

void BUF_AppendToutFxn (  HANDLE *  ph, uint16  timeout, STATUS(*)(uint8 evt, void *parg1, void *parg2)  pfxn )

Set buffer timeout. By default the buffer structure has no timeout callback function associated. This function appends a timeout callback function that will be fired if the fifo contains data that is older that the timeout period. The handle to the buffer structure is passed thrue the parg1 argument of the callback function. Each read or write access on the buffer re-triggers the timer. Note that the callback funcion is executed from the uSMARTX_Tick() context. Parameters: ph  handle to buffer timeout  timeout in system ticks pfxn  address of the callback function Examples: buffer.c.

void BUF_AppendTrgFxn (  HANDLE *  ph, uint16  trigger, STATUS(*)(uint8 evt, void *parg1, void *parg2)  pfxn )

Set buffer trigger level. By default the buffer structure has no trigger callback function associated. This function appends the trigger callback function with a defined trigger level. The function is executed only once and is re-triggered when the buffer is completely emptied out (also BUF_Flush()). The handle to the buffer structure is passed to the function via the parg1 argument. Parameters: ph  handle to buffer trigger  trigger level pfxn  address of the callback function Examples: buffer.c.

void BUF_Flush (  HANDLE *  ph  )

Empty buffer. Parameters: ph  handle to buffer

STATUS BUF_Get (  HANDLE *  ph, void *  pdata )

Get data from buffer. If there is some data in the buffer this function retrieves it. Each read access on the buffer also reset the associated timeout callback function timeout. Parameters: ph  handle to buffer pdata  pointer to where the data will be written Return values: SYS_OK  data was retrived from buffer SYS_ERROR  there was no data in buffer Examples: buffer.c.

STATUS BUF_Put (  HANDLE *  ph, void *  pdata )

Put data into the buffer. This function writes data into the buffer if there is enough free space. If there is a trigger function set and the function has reached the trigger level the trigger callback function is executed. Note the execution context is the same as BUF_Put. Each write access resets the timeout callback function timeout. Parameters: ph  handle to buffer pdata  pointer to data to write in Return values: SYS_OK  data was stored into the buffer SYS_ERROR  there was no enough free space Examples: buffer.c.

uint16 BUF_Querry (  HANDLE *  ph  )

Querry buffer. Parameters: ph  handle to buffer

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