Difference between Sequencer, sequence and transaction ?

[swapnilm]

Dear all,

Can anyone please tell me the actual difference between A sequencer, A sequence and transaction? Its so confusing. Any guidance would be appreciated. Thanks.

Swapnil

[rajneeshT]

Hi

Sequencer is a stimulus generator which returns random data item when requested by driver.

Using sequence we can add constraints to generate controlled randomized values of stimulus..

Transaction is the input to the DUT from driver component.

Sequence -(provides control on distribution of randomized values)----> sequencer --(generates randomized stimulus when requested by Driver)----> transaction sent to DUT

Thanks,

[swapnilm]

Thanks for your reply Rajneesh. So it means, that transactions make sequence. These sequences can be one or many. The sequences will consist of randomised values of transactions(data items or sequence items). And these sequences will be sent by the sequencer to the driver upon its request. Sequencer actually controls the flow of these sequences from sequencer to the driver. Ultimately these transactions or data items, will be passed on to the DUT after the driver finishes its execution upon transactions. Right? Please correct me if I am wrong. Thanks in advance.

[rajneeshT]

Yes, you are right.

[swapnilm]

Thanks Rajneesh for your reply.

[Hash]

UVM code for a sequence must contain task_body() ,this is the one basic difference between sequence &sequencer

[swapnilm]

Thanks Hash, can u also reply for hello world query I put in the forum. I would appreciate that.