Circuit for the ability to test.

摘要

PURPOSE:To enhance test efficiency by mounting an input/output means performing initial setting of the memory part within a first main module and reading the data from the memory part and a usual operation means usually operating a common bus control circuit and the memory part. CONSTITUTION:When TMOD is set at a level 1 through a test mode control wire lT and a test mode is set, usual operation is stopped. Next, the common bus control data to an instruction register (IR)1c through a test I/O control wire l1 is set. Subsequently, the address of the memory part 4a or 5a of a reading destination is written in an address register (AR)1d through the control wire l1. Next, SICLK is set at a level 1 through a usual operation control wire lS. By this constitution, the data of the memory part indicated by the address in the AR1d is read in a data register (DR)1e through a common bus 40. Finally, the data of the DR1e is read from the control wire l1.