UVVM FIFO Collection

The FIFO Collection is a memory buffer that can be used to hold one or more FIFOs. Each FIFO will be allocated a chosen size and ID number. This allows a selectable number of FIFOs to operate individually and be independently accessed.

Functional Parameters

Name	Type	Description
buffer_idx	natural	The index of the FIFO that shall be initialized
buffer_size_in_bits	natural	The size of the FIFO
entry_size_in_bits	natural	The size of the returned std_logic_vector
data	std_logic_vector	The data that shall be pushed to the FIFO
void	t_void	Unused, empty input parameter

Methods

• All FIFO functions and procedures are defined in data_fifo_pkg.vhd

• All parameters in brackets are optional.

uvvm_fifo_init()

This UVVM FIFO call will allocate space in the FIFO buffer. If no buffer_idx is given, the call will return a buffer index for use when addressing the FIFO. Note that 0 will be returned on error. If a buffer_idx is given, the FIFO is initialized with this index.

uvvm_fifo_init([buffer_idx], buffer_size_in_bits)

-- Examples:
uvvm_fifo_init(C_BUFFER_IDX_1, C_BUFFER_SIZE-1); -- initialize buffer with index C_BUFFER_IDX_1
v_fifo_idx := uvvm_fifo_init(C_BUFFER_SIZE-1);

uvvm_fifo_put()

This procedure puts data into a FIFO with index buffer_idx. The size of the data is unconstrained, meaning that it can be any size. Pushing data with a size that is larger than the FIFO size results in wrapping, i.e., that when reaching the end that data remaining will overwrite the data that was first written.

uvvm_fifo_put(buffer_idx, data)

-- Examples:
uvvm_fifo_put(C_BUFFER_IDX_1, v_rx_data);

uvvm_fifo_get()

This function returns the data from the FIFO and removes the returned data from the FIFO. Note that buffer_idx is the index of the FIFO that shall be read, and that entry_size_in_bits is the size of the returned data as SLV. Attempting to get data from an empty FIFO is allowed but triggers a TB_WARNING and returns garbage data. Attempting to get a larger value than the FIFO size is allowed but triggers a TB_WARNING.

std_logic_vector := uvvm_fifo_get(buffer_idx, entry_size_in_bits)

-- Examples:
v_rx_data := uvvm_fifo_get(C_BUFFER_IDX_1, C_ENTRY_SIZE-1);

uvvm_fifo_flush()

This procedure empties the FIFO given by buffer_idx.

uvvm_fifo_flush(buffer_idx)

-- Examples:
uvvm_fifo_flush(C_BUFFER_IDX_1);

uvvm_fifo_peek()

This function returns the data from the FIFO without removing it. Note that apart from not removing the data, this function will behave in the same way as the uvvm_fifo_get() function.

std_logic_vector := uvvm_fifo_peek(buffer_idx, entry_size_in_bits)

-- Examples:
v_rx_data := uvvm_fifo_peek(C_BUFFER_IDX_1, C_ENTRY_SIZE-1);

uvvm_fifo_get_count()

This function returns a natural indicating the number of elements currently occupying the FIFO given by buffer_idx.

natural := uvvm_fifo_get_count(buffer_idx)

-- Examples:
v_num_elements := uvvm_fifo_get_count(C_BUFFER_IDX);

uvvm_fifo_get_max_count()

This function returns a natural indicating the maximum number of elements that can occupy the FIFO given by buffer_idx.

natural := uvvm_fifo_get_max_count(buffer_idx)

-- Examples:
v_max_elements := uvvm_fifo_get_max_count(C_BUFFER_IDX);

uvvm_fifo_is_full()

This function returns a boolean indicating if the FIFO is full or not.

boolean := uvvm_fifo_is_full(buffer_idx)

-- Examples:
v_fifo_is_full := uvvm_fifo_is_full(C_BUFFER_IDX);

uvvm_fifo_deallocate()

This function de-allocates the FIFO buffer, all the FIFO pointers are reset.

uvvm_fifo_deallocate(VOID)

-- Examples:
uvvm_fifo_deallocate(VOID);

Note

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