Is transaction-based debugging useful ?

[ben cohen]

vhdlcohen@aol.com (VhdlCohen) wrote in message news:<20030817160811.06890.00001541@mb-m06.aol.com>...

Cadence has pushed the transaction-based debugging concept for
many years, but it looks like many designers do not accept this
methodology, could some people out there explain the reasons ?


I like transaction-based modeling for TB because the model distinguishes btween
JOBs or transactions, and low-level interface signals. I used
trasnsaction-based modeling with Verilog and VHDL, but not with Testbuilder.
You can read a white paper at my site, under models and papers.

veriflang.pdf Document: Transaction-Based Verification in HDL
Ben Cohen
--
In actual scenario, in some cases, there could be lot of transactions
not exactly initiated by testbench. There could be protocol
violations
during this time when the testbench is transaction based. I suggest
protocol checker followed by a transaction based testbench.

The TB reacts to the environment. Thus, if the Device Under Test

(DUT)
has a protocol violation casues by correct design (e.g., a mode), then
the TB
should react accordingly. Transaction-based means the following to
me.
1. TB_Client issues a transaction (a task) to a server.
2. Server interprets the task (e.g., READ), and issues the low-level
protocol for the READ.
3. DUT replies using low level protocol.
4. Server collects the received data, using the low-level protocol,
and creates a REPLY transaction to TB_Client.
5. TB_CLient may react to the REPLY transaction according to
requirements.

Now for the checkers: If you use an HDL checker, the checkers reads
the TB_Client and REPLY transactions and dtermines accuracy of
results. A scoreboard may be used by teh checker.

If you use ABV with PSL, you write assertions in your RTL code that
performs during simulation white-box verification. ABV with PSL can
also be used for formal verification without simulation.

How many client/servers do you need, That depends upon the DUT.
In my book "Component Design by Example", I used 2, one set for each
interface of the UART (XMT and RCV).

MY latest book on PSL demosntrates applications of PSL for simulation.
However, the same code with additional verification directives can be
used for fomal verification.
ABV is the new paradigm shift for verification, just like computer
synthesis from RTL was a shift from manual synthesis with schematics.

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Ben Cohen Publisher, Trainer, Consultant (310) 721-4830
http://www.vhdlcohen.com/ vhdlcohen@aol.com
Author of following textbooks:
* Using PSL/SUGAR with Verilog and VHDL
Guide to Property Specification Language for ABV, 2003 isbn
0-9705394-4-4
* Real Chip Design and Verification Using Verilog and VHDL, 2002 isbn
0-9705394-2-8
* Component Design by Example ", 2001 isbn 0-9705394-0-1
* VHDL Coding Styles and Methodologies, 2nd Edition, 1999 isbn
0-7923-8474-1
* VHDL Answers to Frequently Asked Questions, 2nd Edition, isbn
0-7923-8115
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