| 摘要 |
PURPOSE:To enable the accomplishment of monitoring the titled data bus independently of the soft ware in an LSI by a method wherein the output section of the LSI is provided with a substituting circuit for a synchronizing circuit, and a means to output the data on the data bus to the substituting circuit by changing the synchronizing circuit to a just data transfer circuit is provided. CONSTITUTION:In a normal state of operation of the LSI, an enable signal line 6 is supplied with low level signals, and an external latch control signal line 8 with high level ones. Therefore, the data on the data bus 1 in the LSI is latched to a latch 2 and then outputted through a latch 4 under a through condition via driver 3. When the signal level of the signal line 8 is changed to a low level, the latch 2 is made through, producing just the function of data transfer. Thus, practically, the data bus 1 is led out of the LSI via driver 3, its data being latched to the latch 4 being under operating on the latch function made apparent, and its output data being then monitored and offered to required applications. |
