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Universal Analog/Mixed-Signal Assertion with Automatic Activation Feature

IP.com Disclosure Number: IPCOM000241897D
Publication Date: 2015-Jun-05
Document File: 5 page(s) / 402K

Publishing Venue

The IP.com Prior Art Database

Abstract

Assertion based verification (ABV) has been used widely in digital domain for many years. As the analog and mixed signal circuit becomes a more important part in the modern SoC, ABV is gaining more popularity in analog domain, although the parasitic effect in analog design, such as rising and falling delay makes building analog assertion difficult. In this paper, an automatic activation assertion for analog/mixed signal is proposed and implemented. Internal variables and self-adaptive sampling algorithm are employed to record and evaluate the condition of analog signal. Automatic activation is realized based on the two applications. Experiment is conducted to prove the feasibility of this novel analog/mixed signal assertion. The experimental result also indicates that this assertion can be used in the verification work of any kind of analog design.

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Universal Analog/Mixed-Signal Assertion with Automatic Activation Feature


Abstract: Assertion based verification (ABV) has been used widely in digital domain for many years. As the analog and mixed signal circuit becomes a more important part in the modern SoC, ABV is gaining more popularity in analog domain, although the parasitic effect in analog design, such as rising and falling delay makes building analog assertion difficult. In this paper, an automatic activation assertion for analog/mixed signal is proposed and implemented. Internal variables and self-adaptive sampling algorithm are employed to record and evaluate the condition of analog signal. Automatic activation is realized based on the two applications. Experiment is conducted to prove the feasibility of this novel analog/mixed signal assertion. The experimental result also indicates that this assertion can be used in the verification work of any kind of analog design.

Keywordsanalog/mixed-signal, automatic activation assertion, internal variable, self-adaptive sampling algorithm

        I.            Introduction

Assertions are originated from temporal logics such as linear temporal logic (LTL) and computation tree logic (CTL). And now, they have extended into industry standards like System Verilog assertion (SVA) and property specification language (PSL). [1-3] Owing to its practicality and simplicity, assertion based verification (ABV) has gained a great deal of popularity in the past decades, especially in the digital design community. In the ABV flow, specific requirements are implemented in assertion statements that are set by designers. These statements monitor the behavior of digital design codes such as RTL, and report any violation during the simulation. [4-6]

Applying the ABV methodology to analog and mixed signal designs can bring the same benefit as that of digital designs. As shown in  Figure.1, analog signal is monitored and checked by specific assertion. [7-8] The glitch and abnormal vibration of this signal could be captured by the analog assertion statement.

However, due to the parasitic effect in analog design, each output signal needs different delay time to reach the stable state. All of these delay times have to be estimated or checked by designers before activating the assertion. As a result, the assertion statements must be modified based on the special design and are not re-useable in different designs. Unfortunately, as the scale of analog/mixed signal design is becoming much larger than that of decades ago, the manual effort to build assertion checkers is too ineffective to be accepted by designers, and it also degrades the efficiency of ABV.

Figure.1 DA_IP verification environment

In this paper, an analog assertion with internal variables [9] and self-adaptive sampling algorithm [10] is introduced. Internal variables and self-adaptive sampling algorithm are used to evaluate the situation of analog signal and to decide whether the assertion can be activated. Thanks t...