| 摘要 |
PURPOSE:To evaluate and inspect a fuse matrix for a user, and the characteristic of a fixed logic circuit by using a test circuit before writing information, by assembling a compressed testing fuse matrix, and fixed logic circuit. CONSTITUTION:By supplying a voltage higher than a normal input voltage to a fixed input out of input pins IO-IN, a switching circuit 6 is operated, and the test circuit is selected. A bit of fuse write information developed by an expected logical expression is inputted from output pins IO-IN, and the input pins IO-IN, and is written through a write control circuit 5. Next, by impressing an input condition to verify a testing fixed logic circuit 8 on the input pins IO-IN, an output appears at the output pins IO-IN through an output circuit 4. By comparing a result outputted at the output pins IO-IN with an expected value, and also, applying a test for a circuit characteristic, etc., abnormality in the fuse matrix, and the fixed logic circuit due to the process fluctuation of a PLA IC can be confirmed without using a user circuit. |
