| 1. | And more than 70 % hardware are tested during microcode self - test since the execution of micro program can cover other data paths . boundary scan is designed according to ieee1149 . 1 , and some other instructions such as degug , runbist are provided to support internal fault testing , online debugging and built - in self - test besides the several necessary insructions . internal scan is implemented by partial scan , through this the boundary of logic component and user - cared system registers can be selected to be scanned
Bist用于测试cpu的微码rom ,其它ram则利用微码rom中的微程序进行测试,而微程序的运行则可以顺带覆盖其它数据通路,从而使高达70 %的硬件得到测试;边界扫描按ieee1149 . 1标准设计,除必备的几条边界扫描指令外,还提供了debug 、 runbist等指令以支持内部故障测试、在线调试及内建自测试;内部扫描采用部分扫描策略,选择逻辑部件的边界及用户关心的系统寄存器进行扫描,从而实现了硬件逻辑划分,方便了后续的测试码产生和故障模拟,并为在线调试打下了基础。 |
