Abstract: For a test operation on a main circuit without supplying a test signal from a test unit, an integrated circuit device includes, a supplementary or test circuit in addition to the main circuit. A test signal is produced in the test circuit and is supplied to the main circuit. Responsive to the test signal, the main circuit produces a data signal. The test circuit processes the data signal into a result signal representative of a result of the test operation. The result signal is supplied to a peripheral or test unit which is well known in the art. It is preferable that the test circuit carries out the test operation with reference to a combination of a particular signal having a predetermined cycle and a particular phase and a specific signal having the predetermined cycle and a specific phase which is different from the particular phase.

Abstract: A time of day coincidence system for coinciding time of day values of a plurality of apparatuses includes a clock pulse generator for generating clock pulses having a predetermined interval, a TOD time of day timer controlled by the clock pulse, a time of day correction signal generator for generating a correction signal in a predetermined interval which is a predetermined multiple of the count cycle of the TOD timer. The clock pulse generator, the TOD timer, and the time of day correction signal generator are arranged commonly for the apparatuses. The system also includes a counter, a count of which is incremented in response to the clock pulse, a time of day read and set unit for reading out current time of day information from the TOD timer in response to an external instruction and setting the time of day information in the counter, and a time of day correction unit for correcting the count of the counter in response to the correction signal in accordance with a predetermined rule.

Abstract: A data processing unit diagnosis control apparatus comprises a microprocessor, a memory device, a data transfer circuit and a diagnostic processor. The diagnostic processor performs a diagnostic program of a data processing apparatus to be diagnosed. The diagnosis program is supplied from the memory device via the data transfer circuit under control of the microprocessor which issues an appropriate instruction to the data transfer circuit. The microprocessor is subsequently able to operate on other programs while the diagnostic processor executes the diagnostic program.