SN74ACT8990芯片在数字电路测试中的应用

Applications of SN74ACT8990 in Digital Circuits Test

SN74ACT8990作为测试总线控制器,主要用于测试数据的交互,是基于边界扫描技术的数字电路测试的核心部件;为了解决上述新兴测试技术在实际应用方面研究的不足,首先介绍了芯片的功能、基本结构以及工作原理;从硬件电路和程序设计两个方面,分别详细地介绍了一个典型的基于SN74ACT8990边界扫描测试系统的设计方法及过程;最后利用测试指令扫描和互连测试对设计的测试系统进行了功能验证;结果表明,在数字电路测试中,采用基于SN74ACT8990的边界扫描技术能够准确地定位故障,并能初步判断故障类型,具有较高的测试效率和广阔的应用前景。

SN74ACT8990 is a test bus controller used for the interaction between test data, and is the chief part of a boundary--scan based test of digital circuits. Taking the new test technology＇ s deficiency of the practicality application into account, the chip＇ s functions, basic structure and application principles are presented. Secondly, a SN74ACT8990 based boundary--scan test system＇ s design is separately introduced from the hardware to software. At last, a test instruction scan and a interconnection test are used to verify the test system. The results indicate that the SN74ACT8990 based boundary--scan test technology embodied with higher test efficiency can locate the faults exactly, can identify the faults＇ type and can be widely applied in the test of digital circuits.