By means of one comparator circuit and one multiplexer, when the program execution reaches the error segment in ROM, it is changed to execute the corresponding correct program codes in RAM.

• 经由一比较电路及一多路复用器的作用，在程序执行到只读存储器中的错误区段时，转而执行存储在随机存取存储器中所对应的正确程序码。