Altera Mentor Verification IP Altera Edition AMBA AXI4-Stream - Manual (Page 84)

Mentor Verification IP AE AMBA AXI4-Stream User Guide, V10.3 84
VHDL API Overview
Operational Transaction Fields
April 2014
Operational Transaction Fields
Operational transaction fields control the way in which a transaction is executed onto the
protocol signals. These fields also indicate when an individual data transfer or transaction is
complete.
Operation Mode
By default, each transaction performs a blocking operation that prevents a following transaction
from starting until the current active transaction completes.
You can configure this behavior to be nonblocking by setting the operation_mode transaction
field to the enumerate type value AXI4STREAM_TRANSACTION_NON_BLOCKING
instead of the default AXI4STREAM_TRANSACTION_BLOCKING.
Example 7-11 shows a master BFM test program creating a transaction by calling the
create_master_transaction() procedure. Before executing the transaction, the operation_mode
is changed to nonblocking.
Example 7-11. Master Test Program set_operation_mode() Procedure
-- Define a local variable trans to hold the transaction record.
variable trans: integer;
-- Create a master transaction with 10 transfers.
create_master_transaction(10, trans, bfm_index,
axi4stream_tr_if_0(bfm_index));
// Change the operation_mode to be nonblocking in the transaction record
set_operation_mode(AXI4STREAM_TRANSACTION_NON_BLOCKING, trans, bfm_index,
axi4stream_tr_if_0(bfm_index));
In the above example, the bfm_index specifies the actual master BFM.
Handshake Delay
You can configure the TVALID and TREADY handshake signals to insert a delay before their
assertion.
TVALID Signal Delay Transaction Field
The Transaction Record contains a valid_delay transaction field to configure the delay of the
TVALID signal. The setting of the valid_delay transaction field is performed in the master
BFM test program by calling the
set_valid_delay() procedure.