Apparatus and method for testing circuit units to be tested

1. Test apparatus for testing a circuit unit to be tested, the test apparatus comprising:

a) a nominal data production unit for production of a nominal data stream, which can be supplied to the circuit unit to be tested;

b) a comparison device for comparison of an actual data stream which is emitted from the circuit unit to be tested as a function of the nominal data stream that is supplied with the nominal data stream;

c) a compression device for compression of an intermediate result signal which is emitted from a comparison device as a function of the comparison into a test result signal, wherein the compression device has at least one logic circuit which is in the form of an AND function, such that the test result signal indicates fault-free operation of the circuit unit to be tested only when each of the intermediate result signals indicates fault-free operation of the circuit unit to be tested; and

d) a buffer storage device for temporary storage of the intermediate result signal which is emitted from the comparison device, only if the test result signal indicates that the circuit unit to be tested is faulty,

e) wherein, the test apparatus further comprises a read unit for reading the intermediate result signal which is temporarily stored in the buffer storage device, wherein the read unit is designed so as to subdivide the intermediate result signal which is temporarily stored in the buffer storage device into separate result blocks.

2. Apparatus according to claim 1 , wherein the compression device for compression of the intermediate result signal which is emitted from the comparison device is designed such that the test result signal comprises 1 bit of information.

3. Apparatus according to claim 1 , wherein the test result signal has a length of 1 bit.

4. Apparatus according to claim 1 , wherein the actual data stream comprises odd-numbered actual data and even-numbered actual data.

5. Apparatus according to claim 1 , wherein the nominal data stream and/or the actual data stream have/has a length of 32 bits.

6. Apparatus according to claim 1 , wherein the intermediate result signal which is temporarily stored in the buffer storage device has a length of 32 bits.

7. Apparatus according to claim 1 , wherein the result blocks which are produced by the read unit and are produced by subdivision of the intermediate result signal which is temporarily stored in the buffer storage device have a length of 8 bits.

8. Method for testing a circuit unit to be tested, in a test apparatus, the method comprising:

a) producing of a nominal data stream by means of a nominal data production unit;

b) supplying of the nominal data stream to the circuit unit to be tested;

c) comparing of an actual data stream which is emitted from the circuit unit to be tested as a function of the nominal data stream which is supplied with the nominal data stream by means of a comparison device;

d) compressing of an intermediate result signal which is emitted from the comparison device as a function of the comparison into a test result signal, by means of a compression device, wherein the compression device carries out a logic AND operation such that the test result signal indicates fault-free operation of the circuit unit to be tested only when each of the intermediate result signals indicates fault-free operation of the circuit unit to be tested; and

e) temporary storing of the intermediate result signal which is emitted from the comparison device in a buffer storage device, only if the test result signal indicates that the circuit unit to be tested is faulty; and

f) reading of the intermediate result signal which is temporarily stored in the buffer storage device by means of a read unit, wherein

f1) the read unit subdivides the intermediate result signal, which is temporarily stored in the buffer storage device, into separate result blocks, and wherein

f2) the result blocks which are emitted from the read unit are read via an address bus of the circuit unit to be tested.

9. Method according to claim 8 , wherein the intermediate result signal which is emitted from the comparison device is compressed in the compression device into 1 bit of information.

10. Method according to claim 8 , wherein the test result which corresponds to a test in the circuit unit to be tested is emitted as a test result signal with a length of 1 bit via an output line from the compression device.

11. Method according to claim 8 , wherein the actual data stream is formed from odd-numbered actual data and even-numbered actual data, and is emitted from the circuit unit to be tested.

12. Method according to claim 8 , wherein the nominal data stream and/or the actual data stream are/is in the form of data streams with a length of 32 bits.

13. Method according to claim 8 , wherein the intermediate result signal which is temporarily stored in the buffer storage device is produced as a signal with a length of 32 bits.

14. Method according to claim 8 , wherein the result blocks which are produced by the read unit and are produced by subdivision of the intermediate result signal which is temporarily stored in the buffer storage device are in the form of blocks with a length of 8 bits.

15. Method according to claim 8 , wherein the result blocks which are emitted from the read unit are read via the address bus of the circuit unit to be tested, as a function of a test mode signal which is supplied to the read unit.