Altera Mentor Verification IP Altera Edition AMBA AXI4-St Manuale Utente Scaricare il pdf (Pagina 72)

Mentor Verification IP AE AMBA AXI4-Stream User Guide, V10.3

SystemVerilog Tutorials

Verifying a Master DUT

April 2014

• Task ready_delay() to configure the delay of the TREADY signal.

m_insert_wait

The m_insert_wait configuration variable controls the insertion of a delay for the TREADY

signal defined by the ready_delay() task. To insert a delay set m_insert_wait to 1 (default);

otherwise, set to 0, as shown in Example 6-4.

Example 6-4. m_insert_wait

// This member controls the wait insertion in axi4 stream transfers

// coming from master.

// Assigning m_insert_wait to 0 turns off the wait insertion.

bit m_insert_wait = 1;

ready_delay()

The ready_delay task inserts a delay for the TREADY signal. The delay value extends the

length of a protocol transfer by a defined number of ACLK cycles. The starting point of the

delay is determined by the completion of a previous transfer, or from the first positive ACLK

edge after reset at the start of simulation.

The ready_delay() task initially sets TREADY to 0 by calling the execute_stream_ready() task,

as shown in Example 6-5. The delay is inserted by calling the wait_on() task within a repeat()

statement. You can edit the number of repetitions to change the delay. After the delay, the

execute_stream_ready() task is called again to set the TREADY signal to 1.

Example 6-5. ready_delay()

// Task : ready_delay

// This is used to set ready delay to extend the transfer

task ready_delay();

// Making TREADY '0'. This will consume one cycle.

bfm.execute_stream_ready(0);

// Two clock cycle wait. In total 3 clock wait.

repeat(2) bfm.wait_on(AXI4STREAM_CLOCK_POSEDGE);

// Making TREADY '1'.

bfm.execute_stream_ready(1);

endtask

Note

In addition to the above tasks and variables, you can configure other aspects of the slave

BFM by using these functions: “set_config()” on page 48 and “get_config()” on page 49.

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Altera Mentor Verification IP Altera Edition AMBA AXI4-St Manuale Utente Pagina 72