| 摘要 |
PURPOSE:To improve the diagnosis capacity and to shorten the test time by setting the functions of a test function designating terminal to test a mapping array, a control memory and a microinstruction decoder independently of each other. CONSTITUTION:The functions of a mapping array 2, a control memory 3 and a microinstruction decoder 7 are tested independently of each other through a test function designating terminal 27 which supplies selectively the test function via a terminal outside a microprocessor. A control circuit 19 for test function 1, for example, delivers a decoding permission signal of an instruction register 1 to the array 2 and transfers the decoding output to be applied to an address register 4 to a test function register 11. While a decoding inhibition signal is delivered to the decoder 7 to actuate the function 1 only. Then a writing address is set at a data transfer address register 25, and a writing request signal is delivered to a bus transfer control circuit 8. This control action is repeated to test the decoding function of the array 2. |
