| 摘要 |
PURPOSE:To ensure the check for the function of ROM incorporated into LSI with no addition of the checking terminal, by memorizing previously the different numerial value in each address of RAM, designating the address of RAM by the output of ROM, and reading out the contents of the address to outside to be checked. CONSTITUTION:The logic circuit performs the arithmetic control through the control by ROM which memorizes the address of RAM 13 plus various instructions. In such logic circuit, the different prescribed data are memorized previously in each address of RAM13 , and the test signal is supplied to terminal 23 when carrying out a test. And AND circuit 26 is closed via inverter 27 to inhibit the writing to RAM13, and RAM13 is kept under the reading mode. The fixed address data are given to ROM11 via address control part, and at the same time the test address control system of RAM13 is actuated via gate group 25. Thus, the necessary data is read out to external tester 28 through RAM13. |
