| 摘要 |
PURPOSE:To improve both test efficiency and detecting factor with a test circuit for a large scale integrated circuit LSI, by adding such a route that can be connected to an internal bus of a large scale function block like an internal CPU from the outside of the LSI. CONSTITUTION:When a test mode setting signal 19 given from outside becomes active, a test bus connection control signal 21 becomes active and outputted from a test bus connection control circuit 20. Then the test bus connection circuits 16 and 17 connect a bus interface 4 with a test bus 18 as well as a CPU internal bus 15 with the bus 18 respectively. Thus the bus 15 can be directly observed from the outside of an LSI, the interface 4, the circuit 17, the bus 18, the circuit 16 and the bus 15 in order. |
